1. On February 24, 1819, the Adams-Onís Treaty was signed in the District of Columbia, ending a long-standing dispute between the United States and Spain over the boundaries of Florida.

2. The National Museum of Natural History, located on the National Mall in Washington, D.C., was founded on February 24, 1910. The museum is home to over 145 million specimens and is one of the largest natural history museums in the world.

3. February 24, 1969, marked the 100th anniversary of the founding of the Environmental Protection Agency (EPA) in the District of Columbia. The EPA is responsible for developing and enforcing regulations that protect the environment and public health.

4. On February 24, 1982, the Washington Metro's Red Line extension to Grosvenor-Strathmore station in Maryland opened to the public. The inauguration of the new station was attended by several high-ranking officials, including Vice President George H.W. Bush and Prince Charles of the United Kingdom.

5. In 2004, on February 24, the DC Council became the first government in the United States to recognize same-sex marriages performed elsewhere. This was a landmark decision that helped pave the way for legalizing same-sex marriage in the District of Columbia and other parts of the country.