President Barack H. Obama dances with Sgt. Margaret H. Herrera. President Barack H. Obama dances with U.S. Army Sgt. Margaret H. Herrera at the Commander-in-Chief's Ball in downtown Washington, D.C., on Jan. 20, 2009. More than 5,000 men and women in uniform are providing military ceremonial support to the presidential inauguration, a tradition dating back to George Washington's 1789 inauguration. SHARE: Download: Full Size (0.04 MB) Credit: VIRIN: 586576-X-LTN42-001.jpg Photo Gallery