On August 24, 1814, during the War of 1812, British forces marched into Washington, DC and burned down the White House, Capitol and other government buildings, after defeating American defenders at Bladensburg, MD. President James Madison, after convening a war council near the Navy Yard, had armed himself with two pistols and rode out to Bladensburg, but after the battle fled to Virginia before turning northward back into Maryland, staying the night at Brookeville. First Lady Dolly Madison rescued a painting of George Washington from the White House. The city's defenders burnt the Navy Yard to keep its ships and supplies from falling into British hands. A British naval force made its way up the Potomac, but instead of attacking Washington from the river, captured and occupied Alexandria, VA before leaving a few days later. The fires set by the British burned though the following night, but a rainstorm the next day helped put them out.
The above is but a brief summary of the day's events. Read more at The Washington Post.