Groups of 10 people or more need reservations. Capitol South or Union Station. National Parks Service offers a tour of the bell tower with a splendid view of the city. The lines for this tour are normally much shorter than for the Washington Memorial. Federal Triangle or Navy Memorial.
Tours begin every half hour.
Docked near the Navy Museum is a real Vietnam-era destroyer, the USS Barry. Tours are by reservation only. Open Monday through Friday except on Federal holidays. No tours are given during August. Capitol South or Union Station.