Completed in 1937, which hiking trail of about 2,000 miles passes through 14 states?

Completed in 1916, which Russian railroad is the longest in the world? Completed in 1930, which William Van Alen skyscraper in New York City is in the Art Deco style? Completed in 1931, which building rises more than 1,400 feet at 350 Fifth Avenue in New York City? Completed in 1932, which monument bears the inscription "Here rests in honored glory an American soldier known but to G… Completed in 1937, which bridge cost about $35 million to build? Completed in 1942, which dam on the Columbia River contains about 12 million cubic yards of concrete? Opened in 1955, which bridge crossed the Hudson River near Nyack, New York? Completed in 1965, which monument towers 630 feet over St. Louis?