An ancient capital city that dates back 3,000 years and harbors many surprises.

This Irish museum in a historic 19th century market pays tribute to the glory of butter.

Built on a medieval synagogue, this church has a burial crypt, tunnel system, and Jewish ritual bath hiding deep underneath.

Italian cave with exceptional acoustics and an unsavory history.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This Stone Age solar temple aligns with the sun on each equinox and solstice.

The fishing boats that moor in this small lagoon enter and leave through a tunnel to the sea.

Two geological phenomena in one precarious locale: a towering stone window, and a deep blue void.

This is one of the very few intact windmills built by the Knights of St. John in the island nation of Malta.

These clocks tell time in a theological sense.

Despite the name, these small saltwater swimming pools have nothing to do with the Romans.

These temples are among the oldest free-standing stone buildings in the world.

At more than 5,000 years old, these structures are among the oldest free-standing stone buildings in the world.

Burial grounds for more than 1,000 bodies deep under the modern town of Rabat.

The floor of this spectacular Baroque sanctuary is covered in memento mori.

Walk through Czech history in Prague's largest graveyard.

P-town goes wild for the malassadas at this 87-year-old institution.

A grand New York post office that is home to mailman Santas, scraps of postal history, and a pneumatic mail system.

This Manhattan museum houses one of the largest collections of Spanish art and manuscripts outside of Spain.

This Dutch Colonial home is the oldest remaining farmhouse in Manhattan.

A museum capturing one of the world's most famous classical composer's battle with hearing loss.

A restaurant and observation deck built in a unique broadcasting antenna.

On the Spree bank, discover one of the last reminders of a symbolic wall that divided, and was torn down by the people.

Designed by Gustave Eiffel before his famed tower.