At over 3 million square feet, this is the largest federal building in Washington, and the only structure for use by both government and private entities. A blend of classical and modern architecture, it is also officially the World Trade Center, Washington, D.C. The Reagan Building hosts a number of special events and exhibitions throughout the year, in addition to its permanent art collection including a 3-ton, 9-by-3-foot section of the Berlin Wall and dramatic sculptural pieces. You'll also be able to see the plans for the Dwight D. Eisenhower Memorial (slated for completion in 2016 on Capitol Hill); as well as the Make it in America and Woodrow Wilson Presidential Memorial Exhibits. Free guided tours of the Reagan Building are offered Monday, Wednesday, and Friday at 11. There's a food court on the lower level, and a theatrical group, the Capitol Steps, performs works of political satire in the Amphitheater on Friday and Saturday nights at 7:30. During the summer months, check out Live!, a free concert series, on Woodrow Wilson Plaza, performed daily from noon to 1:30. A farmers' market, with demonstrations by local chefs, takes over the plaza on Friday during the spring and summer.