The Washington Monument, also known as the obelisk, is the most prominent landmark in Washington, D.C., and presumably the place where visiting Washington is bound to punch in. What many people don't know is that the inside of the monument can be visited. If you go to the tourist center next to the monument in advance and get free tickets (daily limit), you can enter the inside, climb the elevator and go to the viewing platform at the top of the monument. However, this open visit is often stopped because of maintenance, so it's also a matter of luck to enter when you come. An interesting fact is that no building in Washington, D.C. can be taller than the Washington Monument, which is why there are not many skyscrapers in Washington.