Las Vegas for a long time existed primarily as a wide spot on the road on the Old Spanish Trail. It had water and thus was a good spot to rest your team on the way between Santa Fe and Southern California. Las Vegas means "the meadows" in Spanish. When the Mormons started settling in Utah, it acted in the same role for their trips to the coast and back. When the railroad came through it became a watering station. And then it did the same for the highways and eventually I-15. It has always been an important way station for folks on the way to Southern California.

Permanent occupation had to wait till the late 19th century. Brigham Young had tried and then abandoned a settlement in the 1850s. A few decades later some developers tried again and got a small mostly Mormon farming community started. And even today Las Vegas is about 1/3 LDS. Ever since the 1850s there were also a series of mines in the area, silver and lead primarily. And Las Vegas became a good central hub for the miners to ship out their goods, pick up supplies, and spend their cash on booze, women, and gambling. Although eventually the gambling was outlawed.

By the late 1920s it was a small town of around 5,000 supporting the needs of the local farmers and miners, as well as travelers passing through. In 1929 this changed. The Feds started building Boulder Dam (now Hoover Dam). And 10,000-20,000 men came to Vegas looking for work. Only about 5,000 found jobs. But a lot more men and women found work servicing the needs of the construction workers. Nevada quickly re-legalized gambling and prostitution had never been illegal. And Vegas, which had always had some establishments centered around parting the local miners from their money, found a larger and more lucrative group of men to entertain. The city quickly built such a reputation that the companies building the dam banned travel to Vegas and even leaned on the town to shut down the illegal gambling dens and speakeasies... which apparently didn't accomplish much.

In 1936 the dam was complete and most of the workers moved on. The dam had a crew working maintenance, but nothing like the size of the construction crews. However the dam and Lake Mead were becoming tourist sites. And the first resort style hotel was opened on what would become the strip in 1941. The first modern casino-hotel, the Flamingo, opened in 1946. By the 1950s the modern city was taking shape. Vegas was an easy trip up from LA and a series of casinos opened to outdo one another to grab the biggest talent for their shows to draw in the crowds. Most of the casino standards were in place by then.

Basically the little town that had always had a strong service and entertainment tradition for miners and travelers grew up by first serving the needs of the greatest construction project of the early 20th century and then by becoming a destination resort city.