Six times a day a train runs right through the middle of this Thai street market, sending vendors scrambling.

The only arched bridge made of stone on the entire Mississippi River.

When flour explodes, it's not a pretty sight.

Elvis's own personal tropical hideaway.

The hotel where Martin Luther King Jr. was shot is now a museum dedicated to his work.

These stairs were built to accommodate royals mounted on elephants.

A 17th-century mosque that was used for war more than worship.

This lost city belongs to one of the earliest civilizations in the world.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

Where commuters walk through remnants of an ancient Greek necropolis.

This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

This legendary city has been a tourist attraction for centuries.

Gaudí's famously flamboyant architectural style is on full display in this sprawling park and garden.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A more chill but no less fascinating version of the famous ancient archeological site.

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

Gladiators battle and chariots race daily in the ruins of a once-great Roman city.

The world's oldest map of the holy land gives us a fragmented glimpse of the layout of biblical nations.

The most gigantic, swoony, intimidating trio of fingers in all of antiquity.

This dangerous-looking suspension bridge may have been too unstable to remain open.

A small museum in the Golden Triangle tells the story of the opium drug trade that gripped Northern Thailand.

5,000 skulls in memorial to those killed by the Khmer Rouge.

This collection of reclaimed landmines acts as both an exhibition of their deadly history and as a shelter for children affected by them.