The 5.5-mile ring of steel posts around the Capitol Building is one of the largest (and most uniform) of its kind in the world.

The first memorial dedicated solely to the Black troops who fought for the Union.

Largest Roman Catholic church in North America.

A historic arena where the Beatles played their first concert in the U.S.

The longest escalator in the Western Hemisphere takes over three minutes to ride down.

A local farm's collection of unusual structures from a now defunct storybook amusement park.

Rediscovered after a century, the father of the American Navy was reinterred in something dredged up from Davy Jones' Locker.

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

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

A collection of artifacts from Maryland's maritime past.

America's first nuclear-powered merchant ship is now a time warp to the atomic age.