Colorado is nicknamed the Rocky Mountain State for its most prominent geographic feature, giving it the highest mean elevation among the states. Denver is the capital and principal city. Most of the state's economy is devoted to manufacturing, ranching, mining, and tourism. The latter includes skiing as well as visits to Rocky Mountain National Park and the ancient cliff dwellings of Mesa Verde National Park. The Spanish laid claim to the area in 1706, but the land came under US control after the Louisiana Purchase (1803) and Mexican-American War (1848). Colorado achieved statehood in 1876.