U.S. Secret Service officers escort the presidential limousine down Pennsylvania Avenue enroute to the White House

U.S. Secret Service officers escort the presidential limousine carrying President Barack Obama and first lady Michelle Obama on Pennsylvania Avenue enroute to the White House January 20, 2009. Barack Obama became the first black U.S. president on Tuesday and declared it is time to set aside petty differences and embark on a new era of responsibility to repair the country and its image abroad.
REUTERS/Doug Mills/Pool (UNITED STATES)