Colorado is geographically diverse. With its eastern fertile plains to its hilly and semi-mountainous central slopes, to the high alpine conditions of the west, Colorado enjoys a diversity of land and climate. An industrious state, with ample manufacturing, agriculture, electronics and aerospace technology, Colorado is the home of the U.S. Air Force Academy. Eastern Colorado was acquired during the Louisiana purchase in 1803 and Lt. Zebulon M. Pike explored the area in 1806 discovering Pike's Peak. After the Mexican War from 1846 to 1848 substantial immigration occurred in the eastern plains of Colorado. Colorado is known for its average of 310 sunny days a year, more than 1,000 mountains over 10,000 feet and it is the home to 35 major ski areas. Famous Coloradans include Scott Carpenter, Jack Dempsey, Mamie Eisenhower and Douglas Fairbanks. @