Spokane has a rich Native American heritage, which is evidenced from many of the cultural attractions and museum exhibits, right down to the city's name, which is derived from the local tribe, the Spokanee, which translates into the "Children of the Sun." Spokane originally attracted many native american tribes prior to the 20th century due to the abundance of salmon in the Spokane river. The technological advancements of settlers, however, brought an end to the salmon population with the advent of hydroeletric dams installed at the turn of the century. Settlers began trickling in around 1880 when the Northern Pacific Railroad was being built, and upon its completion in 1881, Spokane had developed a european population sufficient to deem Spokane, named "Spokane Falls" at the time, an official city. At the turn of the century, it took a mere ten years for the city's population to triple, reaching over 100,000 people. Spokane was the first U.S. city to celebrate Father's day in 1910, and was also the smallest U.S. city to ever host a World's Fair, which it did in 1974 for the ecologically themed expo. The '74 World's Fair acted as a catalyst for Spokane to shed its old railroad industry ties and become a hub for a new environmentally conscious generation.