The National Postal Museum, a Smithsonian Institution museum, is located in the old Post Office building next to Union Station in Washington, D.C. The Museum was created by an agreement between the Smithsonian Institution and the United States Postal Service in 1990 and opened to the public in 1993. In addition to the stamps, the museum has postal stationery, postal history material that pre-dates stamps, vehicles used to transport the mail, mailboxes, meters, greeting cards, covers and letters.