Autochrome by Howell Walker

Union Station (Massachusetts and Delaware Avenues N.E.; phone: +1 202 371 9441)

This monumental beaux arts building was completed in 1908 and restored in 1988 after years of neglect. The Great Hall and the East Hall have high vaulted ceilings and are sometimes still used for Inaugural Balls. The West Hall now harbors a cache of great shops, and the basement offers a large food court. And, with Amtrak and the Metro, it’s still a busy train station.