Illinois

The largest science museum in the western hemisphere, Chicago's Museum of Science and Industry contains more than 35,000 objects and nearly 14 acres of interactive exhibits.

Completed in 2006 by artist Anish Kapoor, Cloud Gate is a highly reflective work of public art in Chicago's Millennium Park. Inspired by liquid mercury, it is made of 168 stainless steel plates welded together with no visible seams.

Now officially named the Willis Tower, this 1973 Chicago skyscraper is the tallest building in the western hemisphere at 1,450 feet.

Now a state historic site, the Old State Capitol has hosted several important political events, including Lincoln's "House Divided" speech, Lincoln's laying-in-state following his assassination, and Obama's announcement of his candidacy for president.

The center of Mississipian Indian culture from 900 to 1300, Cahokia was the largest pre-Columbian community in North America and produced several ritual earthwork mounds. The site is located in Illinois, just across the state border from St. Louis.