Take a relaxing ride from Philadelphia to Washington D.C. aboard an Amtrak train. By late morning, arrive at Union Station, where you are free to explore the city at your own pace. Step aboard a double-decker bus and embark on your tour.

Hop on and off at any of the stops to enjoy the city's museums, landmarks, and monuments. Possible sites include the towering Washington Monument, the impressively lifelike Lincoln Memorial, and the sobering wall of the Vietnam Memorial, commemorating those who lost their lives in combat. Visit the National Archives, containing the signed Declaration of Independence, or any of the Smithsonian Museums lining the National Mall, including the National Air and Space Museum and the National Museum of Natural History.

Once hunger strikes, make your way city centre, just steps from the National Mall, for a 2-course lunch at Hard Rock Cafe. After lunch, snap photos alongside all 44 US Presidents at Madame Tussauds interactive wax museum, and learn covert secrets of the CIA and FBI at the immersive International Spy Museum. See Ford's Theatre and Museum—the location of President Abraham Lincoln's assassination.

Late in the afternoon, return to Union Station to admire its 1908 architecture, saved from demolition in the 1980s and restored to its original glory. After a day of sightseeing, an Amtrak train whisks you back to Philadelphia by evening.