President Obama gives his inauguration address at his ceremonial swearing-in ceremony during the 57th Presidential Inauguration, Monday, Jan. 21, 2013, on the West Front of the Capitol in Washington. Click to enlarge. (AP Photo/Rob Carr, Pool)

A sea of people flooded the National Mall - from the U.S. Capitol to the Washington Monument, visible in the distance - to watch President Obama inauguration for his second term.

More photos from the day here. And even from space, here.