The Burning of Washington:

The Burning of Washington: 
August 24, 1814
A pivotal moment in American history when British forces invaded the capital during the War of 1812, systematically destroying public buildings including the White House and U.S. Capitol.
The British Invasion of Washington
The Burning of Washington occurred on August 24, 1814 after the British defeated the American forces at the Battle of Bladensburg. As the British army of approximately 4,000 troops approached, led by Major General Robert Ross, the majority of the 8,000 Washington DC residents fled the city. That evening, the vanguard of the British army reached Capitol Hill and began its systematic destruction of all public buildings including the White House and U.S. Capitol, which were largely destroyed.
Spared Buildings
The only buildings to escape destruction were the Marine Corp Barracks and Commandant's House, which US Marine Corp legend attributes to a gesture of respect for their conduct at the Battle of Bladensburg.
American Preemptive Destruction
The Americans already had burned much of the historic Washington Navy Yard, founded by Thomas Jefferson, to prevent capture of stores and ammunition as well as the 44-gun frigate USS Columbia and the 18 gun USS Argus, both new vessels nearing completion at the time of the invasion.
The aftermath of the British attack left Washington's government buildings in ruins, a devastating blow to the young nation's morale and infrastructure.