1. In 1800, May 10 marked the day when the newly formed District of Columbia officially became the seat of the United States government. This was when President John Adams approved the act of congress that moved the federal government from Philadelphia to Washington D.C.

2. On May 10, 1862, during the Civil War, Union forces led by General George B. McClellan launched a major offensive against Confederate forces led by General Joseph E. Johnston in Virginia. The battle, known as the Battle of Williamsburg, was a Union victory and marked a turning point in the war.

3. The Washington Post was first published on May 10, 1877. Over the years, it has become one of the most widely read newspapers in the country and is known for its in-depth reporting on national and international news.

4. On May 10, 1954, the Supreme Court of the United States issued its landmark ruling in the case of Brown v. Board of Education. The ruling declared that segregation of public schools was unconstitutional, paving the way for desegregation in the South and helping to bring an end to the era of Jim Crow laws.

5. In 2015, May 10 marked the beginning of Capital Pride Festival, an annual celebration of the LGBTQ+ community in Washington D.C. The festivities include a parade, concerts, and a street festival, and draw thousands of people from around the country each year.