Original: Las Vegas was established as a railroad town on May 15, 1905, when 110 acres (44.5 ha) owned by Montana Senator William A. Clark's San Pedro, Los Angeles and Salt Lake Railroad, was auctioned off in what is now downtown Las Vegas.
Simplified: In 1905, 110 acres owned by William A. Clark, on which he built a railroad to Southern California were auctioned and Las Vegas was founded as a railroad town.