1. The first recorded instance of Halloween being celebrated in Washington D.C. goes back to 1885, when the Evening Star newspaper reported that groups of children were going around the city in costumes and requesting treats.

2. In 1948, President Harry Truman was the first president to officially celebrate Halloween in the White House. He hosted a costume party for his daughter, Margaret, and her friends.

3. In 1965, the National Archives held an exhibition of original documents related to the Salem witch trials, which occurred in the late 1600s. The exhibit included a copy of the warrant for the arrest of Sarah Good, one of the women accused of witchcraft.

4. In 1984, the Smithsonian American Art Museum held an exhibition featuring the work of Edward Gorey, a popular illustrator and author of macabre stories. The exhibit included drawings, books, and other items related to Gorey's life and work.

5. In 1993, the U.S. Postal Service issued a set of commemorative stamps featuring classic horror movie characters, including Dracula, the Wolf Man, and Frankenstein's monster. The stamps were released just in time for Halloween and became incredibly popular among collectors.