This year we mark a golden anniversary: The Union Plaza opened on July 2, 1971. It has quite a history … and so does its location.The address Number One Main Street is just a few steps south of a historical marker. There, on May 15, 1905, the San Pedro, Los Angeles, and Salt Lake Railroad auctioned off the heart of what we call downtown Las Vegas. The next year, the railroad completed construction of a Spanish-style depot. It tore down that depot to replace it with a station done in the Streamline Moderne style—a kind of Art Deco. It opened in 1940.