And the fact that Las Vegas resembles a gaudy neon mirage in the desert? Well, surely, no more apt image could apply to a place where dreams — of riches, risks, romance — often go to die.

But Las Vegas is also a place where dreams, large and small, are just as frequently born. Hotel and casino owners dream of founding (or furthering) their financial empires. Singers, dancers, comedians and magicians dream of performing night after night before rapt crowds. The unemployed from all over the U.S. dream of finding work. After all, in the first decade of the 21st century, only one or two American cities grew at a faster pace than Las Vegas. And while the foreclosure crisis of the past few years has hammered Nevada’s biggest city, the bright lights and (seemingly) endless stream of cash are still powerful lures for visitors and would-be Las Vegans alike.

In 1955, 50 years after Las Vegas was founded, LIFE magazine took a rather skeptical look at the boomtown and its prospects for growth in a cover story titled “Gambling Town Pushes Its Luck.” The Loomis Dean images in this gallery, meanwhile — many of which were never published in LIFE — provide some wonderful visual reminders of just how raw a place Las Vegas was in the mid-’50s, before the Rat Pack made the city its home away from home and decades before it would begin to reinvent itself as a family-friendly mecca.

Some of the pictures appeared in the June 20, 1955, issue of LIFE, in an article that described the city as “set for its biggest boom,” with some caveats:

At Las Vegas last week the temperate was up to a torrid 110 degrees and the townsfolk who operate the only large gambling center in the country welcomed the seasonable weather. With it they expected the usual bountiful summer crop of tourists trying out their luck and leaving their money behind. The sign of good times seemed everywhere … But with all this a shadow of doubt fell across Las Vegas, a worry that the boom it was set for has started to wilt.

In the past month, two new top-notch hotels opened. One was the $5 million Dunes, which lugged 120 slot machines in anticipation of the rush. The other was the Moulin Rouge, the first interracial hotel in Las Vegas, which welcomed back whites and Negroes to its accommodations and gambling tables. It had Joe Louis as part-owner and host, and a lively, lovely chorus in its floor show.

Like a gamble on a prolonged winning streak, Las Vegas had the feeling its run of luck couldn’t end. For more than a decade, it had parlayed one prosperous year into a more prosperous next year and went into the expansion more in the spirit of hunch than of calculated economics. The opening of the new hotels and of what Las Vegas hoped would be a new era of money-making was opulent and promising … But when the excitement of the opening died down, the town looked at its new places were customers were scarce and the betting light and wondered: Had Vegas pushed its luck too far?

That question, of course, has come up repeatedly over the years, as the desert city has steadily grown from a 100-acre (40 hectare) railroad town in 1905 to a sprawling metropolis of close to 2 million people today. But no matter the odds, Las Vegas always seems to have one more ace in the hole, one more trick up its sleeve to keep the lights on, the casino floors humming and the dreamers coming back again and again.

But back in 1948, a number of inspired amateur craftsmen — not content with riding mundane, conventional bicycles — took their enthusiasm to another, unlikely level and … well, let’s let LIFE tell it, in the words the magazine used in its December 27, 1948, issue:

“To Webster a bicycle is ‘a light vehicle having two wheels, one behind the other.’ Such a definition theoretically describes the contraptions [seen in the article], but fails to do justice to the imagination of the Chicago chapter of the National Bicycle Dealers’ Association.

“By artfully applying welders’ torches to metal tubing, the chapter’s members transform ordinary, utilitarian bicycles into traveling monstrosities. By far the most outlandish ideas have come from the Steinlauf family, who produced from their bicycle repair shop most of the oddities [shown in the article]. They are hazardous; generally at least one member of the clan is to be found in the hospital.”

Here, LIFE.com offers a selection of photos of these preposterous creations from six long decades ago — mechanistic marvels that belie the famous old saying (which we just made up) that there’s no such thing as a useless bicycle.

During those six long, uncertain years, LIFE covered the war with more tenacity and focus than any other magazine on earth. Twenty-one LIFE photographers logged 13,000 days outside the U.S.; half of that time was spent in combat zones. In tribute to those journalists, and to the men, women and even children who sacrificed so much in the Allied war effort, LIFE.com combed LIFE’s unparalleled archives for some of the greatest pictures made during WWII — often searing, occasionally lighthearted, always memorable images from the streets of Blitz-ravaged London to the sands and jungles of Saipan, Guadalcanal, and Iwo Jima.

Seven decades have passed since the war ended, but the power of these pictures (several of which were never published in LIFE) has barely faded: confronting them today, we’re still dumbstruck by the destruction; we still flinch at the scale of the suffering; and we marvel at the courage of the men and women whose unity of purpose kept the flame of hope alive in the darkest of hours.

Of the indispensable photographs taken during the Second World War, Margaret Bourke-White’s image of survivors at Buchenwald in April 1945 — “staring out at their Allied rescuers,” as LIFE magazine put it, “like so many living corpses” — remains among the most haunting. The faces of the men, young and old, staring from behind the wire, “barely able to believe that they would be delivered from a Nazi camp where the only deliverance had been death,” attest with an awful eloquence to the depths of human depravity and, maybe even more powerfully, to the measureless lineaments of human endurance.

What few people recall about Bourke-White’s survivors-at-the-wire image, however, is that it did not even appear in LIFE until 15 years after it was made, when it was published alongside other photographic touchstones in the magazine’s December 26, 1960, special double-issue, “25 Years of LIFE.”

Pictures, meanwhile, from Buchenwald, Belsen and other camps that LIFE did publish — made when Bourke-White and her colleagues accompanied Gen. George Patton’s Third Army on its legendary march through a collapsing Germany in the spring of 1945 — were among the very first that documented for a disbelieving American public the wholly murderous nature of the camps. (At the end of this gallery, see how the original story on the liberation of the camps appeared in the May 7, 1945, issue of LIFE, when the magazine published a series of brutal photographs by Bourke-White, William Vandivert and other LIFE staffers.)

LIFE photographer Margaret Bourke-White

Here, on the anniversary of the April 11, 1945, liberation of Buchenwald, LIFE.com presents a series of Bourke-White photographs, the majority of which never ran in the magazine, from that notorious camp located a mere five miles outside the ancient, picturesque town of Weimar, Germany. Her justifiably iconic picture of men at the Buchenwald fence suggests the horrors made manifest by the Nazi push for a “final solution”: the Bourke-White photographs here, on the other hand, do not suggest, or hint at, the Third Reich’s horrors; instead, they force the Holocaust’s nightmares into the unblinking light.

In Dear Fatherland, Rest Quietly — her devastating 1946 memoir, subtitled “A Report on the Collapse of Hitler’s ‘Thousand Years’” — Bourke-White recalls the ghastly landscape that confronted the Allied troops who liberated Buchenwald, and her own tortured response to what she, the troops from the Third Army and her journalist peers witnessed and recorded there:

There was an air of unreality about that April day in Weimar, a feeling to which I found myself stubbornly clinging. I kept telling myself that I would believe the indescribably horrible sight in the courtyard before me only when I had a chance to look at my own photographs. Using the camera was almost a relief; it interposed a slight barrier between myself and the white horror in front of me.

This whiteness had the fragile translucence of snow, and I wished that under the bright April sun which shone from a clean blue sky it would all simply melt away. I longed for it to disappear, because while it was there I was reminded that men actually had done this thing — men with arms and legs and eyes and hearts not so very unlike our own. And it made me ashamed to be a member of the human race.

The several hundred other spectators who filed through the Buchenwald courtyard on that sunny April afternoon were equally unwilling to admit association with the human beings who had perpetrated these horrors. But their reluctance had a certain tinge of self-interest; for these were the citizens of Weimar, eager to plead their ignorance of the outrages.

In one of the signal moments of his long career and, indeed, of the entire war, an enraged General Patton refused to recognize that the Weimar citizens’ ignorance might be genuine — or, if it was genuine, that it was somehow, in any moral sense, pardonable. With Olympian wrath, Patton ordered the townspeople to bear witness to what their countrymen had done, and what they themselves had allowed to be done, in their name.

Margaret Bourke-White’s pictures of these terribly ordinary men and women — appalled, frightened, ashamed amid the endless evidence of the terrors that their compatriots had long unleashed — Bourke-White’s pictures remain among the most unsettling she, or any photographer, ever made. Long before the political theorist Hannah Arendt introduced her notion of the “banality of evil” to the world in her 1963 book, Eichmann in Jerusalem, Margaret Bourke-White had already captured its face, for all time, in her photographs of “good Germans” forced to confront their own complicity in an unfathomably barbarous age.

— Ben Cosgrove is the Editor of LIFE.com

Credit: Alfred Eisenstaedt

But in color photos taken before and after the invasion, LIFE’s Frank Scherschel captured countless other, lesser-known scenes from the run-up to the onslaught and the heady weeks after: American troops training in small English towns; the French countryside, implausibly lush after the spectral landscape of the beachheads; the reception GIs enjoyed en route to the capital; the jubilant liberation of Paris itself.

As presented here, in masterfully restored color, Scherschel’s pictures feel at-once profoundly familiar and somehow utterly, vividly new.

NOTE: Information on the specific locations or people who appear in these photographs is not always available; Scherschel and his colleagues simply did not have the means to provide that sort of data for every single one of the thousands of photographs they made. When the locale or person depicted in an image in this gallery is known, it is noted in the caption.

From her earliest days as an actress until late in her career — when she had, against her will, been cast in the public eye as the century’s ultimate Sex Goddess — Marilyn posed for LIFE magazine’s photographers. Many of those pictures never ran in LIFE magazine.

The negatives for the revelatory images seen here were discovered during the years-long effort to digitize LIFE’s immense, storied photo archive — an archive that includes outtakes and entire photo shoots that, for reasons as varied as the subjects they covered, were never published.

Here, then, is a series of stunning shots of the one and only Marilyn, as well as some possible explanations why the pictures never made it into print.

Here, on Mother’s Day weekend, LIFE.com offers a selection of portraits of famous moms (Jackie Kennedy, Shirley MacLaine) with their kids, famous kids (Liz Taylor, Sophia Loren) with their moms and, in a few instances, famous kids with their famous moms.

[See TIME.com's "Top 10 Movie Moms We Wish Were Ours."]

The focus of the gallery, however, is most decidedly not meant to suggest that famous moms are any more worthy of notice than any other mothers anywhere in the world who feed, clothe, encourage, protect, challenge and, ultimately, unconditionally love their kids. Instead, the focus of this gallery is, quite frankly, a simple acknowledgement that, like most everybody else, we’re more or less fascinated by fame.

“Let me tell you about the very rich,” F. Scott Fitzgerald once wrote. “They are different from you and me.” An observation to which he might well have added: “And the famous? They’re a whole lot stranger.”

But whether rich or famous (or neither); whether strange or perfectly, unpretentiously, refreshingly normal, moms deserve recognition simply because, after all — as all of us will readily admit in our more brutally honest moments — moms rule the world. And while devoting one measly day a year to celebrating and honoring mothers everywhere might be a rather feeble way to express our gratitude and love, not to worry. They’re moms. They understand.

Still … would it kill you to pick up the phone once in a while?

As LIFE noted in its July 13, 1953, issue, the historic ascent was hardly greeted with unalloyed goodwill and enthusiasm from all corners of the globe. In fact, international politics and racial pride were quickly thrust into the conversation about Hillary’s and Tenzing’s astonishing feat.

“Everest’s Conqueror’s Come Back,” LIFE roared in one headline in that special issue, then immediately blunted the celebratory tone with a caveat: “They bring thrilling stories of a great deed, but little men besmirch their riotous welcome.”

Thus — in a sad foreshadowing of the often contentious debate that had dogged so many attempts on Everest throughout the years (Is it worth the risk of life and limb? What does the local community get out of it? Etc.) — the very first successful climb to the top of the world’s highest peak sparked some often quite ugly jockeying for credit and supremacy. Jockeying, it should be noted, that both Hillary and Tenzing, who were fast friends, had absolutely nothing to do with, and readily denounced. (Also, while LIFE makes more than one mention of “British climbers” in its reporting, it’s worth recalling, and indeed emphasizing, that Edmund Hillary was a proud, born-and-raised New Zealander. He died in 2008, at the age of 88, in Auckland. Tenzing died two years before Hillary, at age 71, in India.)

“The climbers who conquered Everest,” LIFE wrote, “came down to a world eager to see them, honor them and hear their full story…. They came down to such a welcome — such surging excitement and hero worship — as had never before stirred the steamy lowlands of Nepal.”

The first official welcomers met the mountaineers outside of Banepa [the article continues], 20 miles from Nepal’s capital Katmandu. In the lead was British embassy party, bearing beer and sandwiches; then came the Nepalese to garland the heroes with flowers and sprinkle them with kumkum, a vermilion powder of rejoicing. Devil dancers met that at Bhadgaon, still 15 miles out. The wife of Sir John Hunt, the expedition’s leader, came out to meet him. Tenzing’s wife and their two teenage daughters flew from Darjeeling, India. Word came that an Indian newspaper had raided 12,000 rupees ($2,520) to buy Tenzing a house. Gifts of perfume labeled “Bouquet Mount Everest” were pressed on Hillary and Hunt. At Katmandu the state coach of King Tribhuvan and king himself awaited the climbers, and from far beyond Nepal, from Calcutta and New Delhi and London came news that honors and celebrations were waiting.

To the distress and the half-resentful bewilderment of Colonel Hunt and his British climbers, however, these first wild welcomings carried a clear implication that, in Asia, the real hero of Everest was Tenzing alone. The conquest of Everest, a product of selfless teamwork between Asian and European, was being twisted into an ugly tool of Asian nationalism, inflamed further by the normal British habit of treating the hired Tenzing like a hired man. For a time it seemed the feat might be irreparably besmirched until Tenzing himself, a simple man who called Hillary his “lifelong friend,” restored balance and good humor y agreeing to accompany the British to share the accolades of England.

Today, as men and women continue to test their own mettle on the peaks of the Himalayas and on the heights of other, equally lethal mountain ranges around the globe — and, oftener than is right, losing their lives in the process — the pictures in this gallery are a reminder that for some people, the risks have always, unquestionably, been worth it.

Take the Golden Gate Bridge, 75 years old this year. (It opened on May 27, 1937.) With its immediately recognizable “international orange” — not golden — color, its slender, arcing span and its open, stepped towers so often rising dreamlike above the thick fog that courses through the Gate into the bay on summer afternoons, the Art Deco-inflected masterpiece literally connects San Francisco with Marin County to the north and (with perhaps even greater impact) symbolically connects the entire Bay Area with the wild blue Pacific yonder.

Much like its older, statelier limestone and granite cousin 3,000 miles to the east in Brooklyn, the Golden Gate Bridge seems to have always been there. It’s almost impossible, now, to imagine the lower East River or the Golden Gate itself without those visionary, boldly executed marvels.

Like all great architecture, the Golden Gate Bridge doesn’t feel at all like an imposition on its environment. Instead — and at the risk of incurring the wrath of hardcore nature lovers everywhere — the bridge in some very elemental ways manages to enhance its environment. Powerful, graceful, uniting two distinct (town and country) regions of the nation’s most populous state, it is more than an elegant contrivance of cement and steel. As anyone who has walked, ridden a bike or driven across the thrilling structure — or passed beneath it on a boat, through the intense, choppy, frigid waters — can attest, the Golden Gate Bridge is a grand, audacious, beautiful idea brought to life in concrete in steel. Long may it stand.

And yet today, six decades later, at a time when the prospect of nuclear tests by “rogue states” like North Korea and Iran is once again making headlines and driving international negotiations and debate, the very banality of one long-forgotten atomic test in 1955 feels somehow more chilling than other more memorable or era-defining episodes from the Cold War. After all, whether conducted in the name of deterrence, defense or pure scientific research, the May 1955 blast (the results of which are pictured in this gallery) was in a very real sense routine.

This is not to suggest that the scientists, engineers and other professionals involved at Yucca Flat were somehow cavalier about detonating atomic weapons. But it’s worth remembering that, in the first half of 1955, the U.S. conducted more than a dozen nuclear test explosions in Nevada alone. After a while, the mushroom clouds from these tests, visible from Las Vegas 60 miles away, had become tourist draws. One needn’t be a pacifist, an anti-nuclear crusader or a modern-day Luddite to shudder at the thought of nuclear explosion after nuclear explosion after nuclear explosion — and the lethal aftermath of what such explosions entail — ripping through the dry desert air of the starkly gorgeous American southwest.

Here, in this gallery, LIFE.com presents rare and (mostly) unpublished pictures made in the Nevada desert by photographer Loomis Dean shortly after a 1955 atomic bomb test. These are not “political” pictures. They are eerily beautiful, unsettling photographs made at the height of the Cold War, when the destructive power of the detonation was jaw-droppingly huge — but positively miniscule compared to today’s truly terrifying thermonuclear weapons. As LIFE told its readers in its May 16, 1955, issue (in which some of these photos appeared):

A day after the 44th nuclear test explosion in the U.S. rent the still Nevada air, observers cautiously inspected department store mannequins which were poised disheveled but still haughty on the sand sand in the homes of Yucca Flat. The figures were residents of an entire million-dollar village built to test the effects of an atomic blast on everything from houses to clothes to canned soup.

The condition of the figures — one charred, another only scorched, another almost untouched — showed that the blast, equivalent to 35,00 tons of TNT, was discriminating in its effects. As one phase of the atomic test, the village and figures help guide civil defense planning — and make clear that even amid atomic holocaust careful planning could save lives.

There is, in such words and in such sentiments, an almost unrecognizable optimism — it’s tempting to say, an innocence — that is no longer available to us when it comes to honest discussions of, as LIFE put it, “atomic holocaust.” With conversations about nuclear tests (both theoretical and real) so very much in the news these days, these pictures from more than half a century ago might serve as a quiet reminder of just how horrific and insane the very notion of nuclear warfare really is.