There's a crumbling old mansion inside the Smithsonian National Zoo.

Largest Roman Catholic church in North America.

Politicians, bureaucrats, and military officers gathered in this field near the Capitol to settle their disputes with blood.

This former asylum for Black Americans is haunted by its history of violence and racism.

This abandoned asylum was once a state of the art facility before devolving into one of the most deadly mental institutions in American history.

A hidden alley in urban Baltimore is a haven for graffiti artists.

A collection of artifacts from Maryland's maritime past.

The site where Poe "in great distress, and ... in need of immediate assistance" likely died.

A museum dedicated to exhibiting remarkable outsider art.

This bug-eyed water wheel uses the power of the Sun to clean up Baltimore Harbor.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

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

This simple convenience store sits on the location where the Ouija board was named—and has a plaque to prove it.

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.

The only royal palace on U.S. soil has been a territorial capitol, a military headquarters, and a prison for a queen.

Once home to over 8,000 exiled Hawaiians suffering from Hansen's Disease.

Watch the newest land on the planet form before your eyes.

This black shoreline is made up of exploded lava particles.

These picturesque Hawaiian falls are home to a rare species of fish that uses a special sucker to climb up cliffs.

Football field-sized microalgae production tanks on the Hawaiian coast create a stunning view from space.

Hide from the tourist hordes in these relatively unknown, and unguarded lava caves.

Earth's tallest volcano is sacred to Native Hawaiians, and home to a dozen world-class observatories.

The oldest known university in the world is in Fez, Morocco.