This 19th-century aqueduct provides insights into how water was supplied to Victoria on the island of Gozo before modern plumbing.

This prison on the Maltese island of Gozo is almost 500 years old, and they have the graffiti to prove it.

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

A small cave network was discovered under a home in Xagħra, in 1924 when the owner was digging a well.

A 2000-year-old Roman amphitheater lies just below Guildhall Yard.

A secluded green oasis amidst the towering skyscrapers, bears an unusual moniker that reflects one of the city's oldest guilds.

Rebuilt remains of a temple to Roman god Mithras.

The ruins of a church destroyed by both the Great Fire of London and the Blitz, now turned into a peaceful garden.

Over several decades, one of London’s most iconic city gates was dismantled, moved out of the city, and then moved back.

A prehistoric rock shelter that's literally in someone's backyard.

In the middle of a suburban Denver neighborhood is a cave that once provided solace for a prominent Ute chief and his family.

This tea house was a hand-built gift from Boulder's sister city in Tajikstan.

This deserted Gold Rush town is home to a Masonic lodge that, strangely enough, still holds meetings.

A forgotten 1800s burial vault hides in plain sight beneath a busy downtown Houston bridge.

A former post office turned venue, food hall, and retail center.

Jog (or stroll) down an esplanade of fluctuating and whimsical sculpture works.

A 200-year-old bar in the historic French Quarter refuses to give up its place in history, nor its role in securing ours.

This beautiful building in the heart of Manhattan's Financial District was empty for decades.

This curved Manhattan building was built to house the opulence of John D. Rockefeller's oil empire.

In the middle of a busy airport, a statue honoring the astronaut who told Houston that Apollo 13 had a problem.

A pair of gargoyles peer into unsuspecting passengers at Denver’s conspiracy-packed airport.

This 28-foot-tall milk can contains one of the most whimsical ice cream parlors in town.

Wall to wall taxidermy at Denver's oldest and most exotic steakhouse.

This was once the home of Gahan's Saloon, Denver's most storied speakeasy.