Las Vegas: it's a gas, gas, gas

The gambling capital of the world was built on the flashy effects of neon, helium and argon, which lit up the shadowy Nevada desert. Now the city is paying homage to its bright lights, and the debt it owes to the scientist who discovered how to dazzle the world

Neon: you need to know two things about this gas. The first is that it is, in elementary terms, a relative newcomer; even though it is present in small quantities in the air we breathe, it was identified only a century ago by a French scientist named Georges Claude. The second is that, being inert, neon is intrinsically dull. Oh, unless you pass an electric charge through it, as M Claude did. Do that, and it can light up the desert and dazzle the world.

Neon: you need to know two things about this gas. The first is that it is, in elementary terms, a relative newcomer; even though it is present in small quantities in the air we breathe, it was identified only a century ago by a French scientist named Georges Claude. The second is that, being inert, neon is intrinsically dull. Oh, unless you pass an electric charge through it, as M Claude did. Do that, and it can light up the desert and dazzle the world.

Las Vegas was just a flicker in the eye of the San Pedro, Los Angeles and Salt Lake City Railroad when M Claude announced his discovery. The first neon sign in North America was sold by M Claude's own company in 1923 to a Packard dealership in Los Angeles.

At the time, the Mormons mistakenly believed Las Vegas presented a promised, and morally safe, haven in the middle of the Mojave Desert. By the Thirties, they had lost faith with Las Vegas - and the rest of the world had lost interest in the fact that neon glows red in the dark and that, when mixed with a little mercury, its elementary cousin argon turns bright blue. But Las Vegas had barely begun to experiment with the extreme right-hand side of the Periodic Table of Elements.

Helium radiates a lurid magnolia when suitably fired up; krypton issues a steely silver; while xenon emits the palest blue. These elementary truths helped Las Vegas find its place in the world.

Whatever your desire, especially if it was illegal and/or frowned upon in the rest of the US, it could usually be found in Nevada's largest city. Drinkers could slake their thirsts, gamblers could stake their shirts and lovers could make (or fake) their vows. In short, it was a gas, with neon at the top of the elementary tree.

"Welcome to Fabulous Las Vegas" shrieks the iconic sign. When you see the city's emblem close up, in the unforgiving glare of a Nevada noon, it looks pitifully plain. You spot it as you head north along Las Vegas Boulevard at the intersection with Main Street. Las Vegas Boulevard is stripped down to "the Strip" by almost everybody. All the grand monuments from the turn of the 21st century, from the Venetian to Camelot (not a lottery operator, but a re-enactment of the court of King Arthur) cling to the southern part of the Strip.

Downtown Las Vegas is where M Claude's new gas found its raison d'être, and helped the city claw an identity from the shadowy desert. Neon helped to define Las Vegas, and now the city is returning the favour. Time in Las Vegas seems to revolve around 33 times faster than real life. So the relics that have seen the city through since its foundation in 1905 are, relatively speaking, as ancient as the antiquities in Luxor - established in Egypt 1570BC, established in Las Vegas 1993. This was the same time as the Dunes - a shining light on the strip - was snuffed out. It was imploded to make room for Bellagio, the flashy Italianate hotel-casino (that hyphen welds the two together with a permanence not often found in Las Vegas) where Europe meets America and gambles away the rest of the night.

Las Vegas did not always have such global pretensions. In the early days, the city experimented freely with newly discovered elements on the blank canvas of the Mojave Desert.

Evidence of innovation is scattered around the city, but you have to raise your gaze from the baize gaming tables to see it. Downtown is like an amorphous neon museum, whose exhibits are scattered around the streets. The first item was the horse and rider from the Hacienda, now frozen in mid-leap at the corner of Fremont Street. Other exhibits, such as the flame that illuminated The Flame Bar and Grill, are tucked away in culs-de-sac.

But this month, the definitive exhibition of electrical potential has plugged itself into the traveller's need to know. For the rest of this year, "Neon Unplugged" is on show at the Nevada State Museum, a modest (for Las Vegas) building in Lorenzi Park, a couple of miles west of Downtown.

"Elvis slept here" used to be the boast of the Normandie motel, whose sign has been recovered from the boneyard (scrap-heap) to play a leading part in the new exhibition. "If you wish to bet", goes the catchy slogan of another exhibit, El Rancho, "There's nothing better than roulette."

There is, actually. Place a bet on Oxford to be selected as European Capital of Culture 2003, at the outrageously long odds of 10 to 1, then spend your winnings on a flight to Las Vegas to see the new exhibition. It opens with the long and ridiculously curly R of the Desert Inn - a 1950s casino demolished to make way for La Reve, the city's latest $5bn venture. You can see images of Moulin Rouge, "The resort wonder of the world", now a dowdy shell on Bonanza Avenue but about to be replenished as Las Vegas rediscovers its roots.

Neon wasn't the only experimental element to feature in Las Vegas. In the Fifties, above-ground atomic explosions on the Nevada Test Site, north (but not very north) of Las Vegas were regarded as tourist attractions. Thousands of citizens and tourists flocked to Mount Charleston, 45 miles north of the city, for a radioactive picnic. Binion's Horseshoe Casino produced postcards of the events, while the Sands Motel staged a "Miss Atomic 1957" parade. The fall-out of constant re-invention is the continuous scrapping of Las Vegas heritage. Happily, some of the most ancient signs are preserved in Fremont Street, together with a free light show that puts the "o" into ostentatious.

Among the bright lights, there is a dark side to Las Vegas. Paradise: that was what the destination board on the front of the bus promised. But as the CAT ("Citizens Area Transit") bus lurched from stop to stop along Paradise Avenue, which carves a messy track through the south-eastern wastes of suburban Las Vegas, my self-appointed tour guide in the next seat was not instilling confidence.

"Go any further east along Fremont and it's just crack-heads and whores," she cautioned. "We'll be passing by Crack Alley in a minute or two."

A New Yorker who had just blown $4,300 (£3,000) in a marathon, four-day roulette session, insisted on spelling out in words, as well as figures, the measure of his personal catastrophe: "Forty-three hundred dollars."

Las Vegas takes the world to extremes. Spending time in Las Vegas without spending money in the casinos is to defy the purpose of the place; hey, everyone, let's chip in - you should see the size of the electricity bill. But when it comes to serious gambling, tuition is better than intuition. To help gamblers lose money more slowly, Caesar's Palace offers free blackjack lessons every morning. So long as you understand that the odds are against you, and that in the unlikely event of your being ahead you should quit, there are few more pleasurable ways of losing the odd $50. But bear in mind the gambling maxim: if, after half an hour at the table, you can't spot the sucker - it's you.

Thanks to the physical properties of neon, a trip to Las Vegas can have much the same effect as expensive designer drugs.

The home town of indulgence looks and feels like Toytown for tycoons. But beware staying here too long. On my last evening I got so lost trying to find a way out of Binion's Horseshoe Casino that I had to ask for directions back to real life.

Traveller's guide

Getting there: the only airline with non-stop services between the UK and Las Vegas is Virgin Atlantic, which flies from Gatwick on Thursdays and Sundays. A return fare is typically £500.

Staying there: rates for most Las Vegas hotels are very flexible. At quiet times, particularly midweek, you could pay $79 (£53) for a room in a top hotel such as New York New York. On a Saturday night, the price could rise to $259 (£165).

Neon Unplugged: This exhibition runs until 4 January next year. It is part of the Nevada State Museum; call 001 702 486 5205 for more information, or visit www.nevadaculture.org.