For more than 200 years, U.S. presidents have lived and worked in the executive mansion at 1600 Pennsylvania Avenue in Washington, D.C.—commonly known as the White House. The executive mansion received its nickname in 1798, when its stone exterior was painted white to seal it from moisture and prevent cracking. As the official home of the president, the White House has come to symbolize the power and authority of the U.S. government. Within its walls, decisions are made that affect the lives of all Americans and, very often, the lives of millions of people around the world. Today, many people view the White House as a symbol of leadership and democracy.