The castle still holds traces of the abandoned Roman fort it was built atop.

The modern birthplace of Irish freedom.

The enchanting archway is the only surviving portal into Dublin's lost medieval wall.

An Irish church where an 800-year-old mummy is reaching out of his coffin as if to shake hands.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

London's last remaining public soapbox site has seen speeches from Karl Marx, Vladmir Lenin, and George Orwell.

After nearly 60 years, there's still a bear at Paddington Station looking for help.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

The tallest The Church of Jesus Christ of Latter-day Saints temple in the world soars above the Beltway.

An organ located deep within a cave, whose "pipes" are the geological features of the cave itself.

Moonbows over Kentucky.

The world's longest known cave system.

City law dictates that this mountaintop cathedral containing the heart of a saint is to remain the tallest building in town.

A grand Gothic Revival basilica with stained glass depictions of Montreal's religious history has only one soul resting in its crypt.

Commonly referred to as the most photographed Victorian home in the United States.

The last remaining relic of San Francisco's glittering 1915 Panama Pacific Exposition.

In all of the 29 years it was in operation, no prisoners ever escaped successfully... or so they claim.

Manatees congregate around a power plant's discharge canal where the water is especially warm.

A typical "Old South" manor, once owned by author Anne Rice, served as the setting for several of her witchcraft sagas.

This distinctive Crescent City tradition dates back to the days of horse-drawn carriages.

Once the site of a Native American harvest festival, this humble clearing later played an invaluable role in the birth of jazz.

A small park on Bourbon Street features life-size bronze statues of New Orleans musicians.

After the parade, students throw their beads on the tree hoping for good luck on exams.