Balloon View of Washington, D.C.

Detail of Balloon View

After almost twenty new states joined the nation, the U.S. Capitol had to be expanded in the mid-nineteenth century to include more spacious House and Senate chambers. Architect Thomas U. Walter accommodated some ideas from Captain Meigs. The influential engineer moved the House and Senate chambers to the center of the new wings and surrounded them with offices, committee rooms, and corridors. 

Meigs also devised a large crane to fit inside the Rotunda and hoist nearly 4,500 tons of cast iron and other building materials to construct Walter’s new 287-foot-tall dome. When the Civil War erupted In 1861, most construction in Washington halted, but work on the Capitol Dome continued.