The skyline of Des Moines changed in the 1970s and the 1980s, when several new skyscrapers were built. Additional skyscrapers were built in the 1990s, including Iowa's tallest. Before then, the 19-story Equitable Building, from 1924, was the tallest building in the city and the tallest building in Iowa. The 25-story Financial Center was completed in 1973 and the 36-story Ruan Center was completed in 1974. They were later joined by the 33-story Des Moines Marriott Hotel (1981), the 25-story HUB Tower and 25-story Plaza Building (1985). Iowa's tallest building, Principal Financial Group's 45-story tower at 801 Grand was built in 1991, and the 19-story EMC Insurance Building was erected in 1997.