Spectators holding U.S. national flags watch the presidential inauguration ceremony on the West Front of the U.S. Capitol in Washington D.C., the United States, on Jan. 21, 2013. (Xinhua/Zhai Xi)

The West Front of the U.S. Capitol is seen where the presidential inauguration ceremony is being held in Washington D.C., the United States, on Jan. 21, 2013. (Xinhua/Zhai Xi)

Spectators holding U.S. national flags watch the presidential inauguration ceremony on the West Front of the U.S. Capitol in Washington D.C., the United States, on Jan. 21, 2013. (Xinhua/Zhai Xi)

A spectator holding a U.S. national flag watches the presidential inauguration ceremony on the West Front of the U.S. Capitol in Washington D.C., the United States, on Jan. 21, 2013. (Xinhua/Zhai Xi)