Washington's top-secret Cold War-era doomsday communications tower is located in a small neighborhood park.

Home to items never before seen by the public.

Baltimore's classic clock tower was once topped by a rotating, 20-ton medicine bottle.

Once America's tallest structure, now a Baltimore landmark.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

Ship skeletons haunt Baltimore's waterways.

Once home to seven different roller coasters, Glen Echo has undergone many transformations since its founding in 1891.