1. In 1856, the "Sacking of Lawrence" occurred in Kansas Territory, which was then part of the United States. It was a violent incident that was part of the larger conflict over whether Kansas would enter the Union as a free or slave state.

2. In 1965, a power failure hit the Washington D.C. area, leading to widespread blackouts and chaos. It was later determined that a transformer at a power station in Maryland had failed, causing a chain reaction that knocked out power in many parts of the city and surrounding areas.

3. On June 17, 1972, five men were caught trying to break into the Democratic National Committee's headquarters in the Watergate complex in Washington D.C. This would eventually lead to the Watergate scandal, which exposed political corruption and led to the resignation of President Richard Nixon.

4. In 1987, a Continental Airlines DC-9 crashed near the Potomac River in Washington D.C., killing 73 people. The crash was caused by a combination of bad weather, pilot error, and mechanical problems.

5. In 2015, nine people were killed in a shooting at a historic African-American church in Charleston, South Carolina. While the incident did not happen in Washington D.C., it had a profound impact on the nation and led to renewed conversations about gun control and racial tensions.