A fiery crater has been burning in the Karakum Desert since 1971.

A repurposed railway tunnel with otherworldly acoustic characteristics.

The spot where the two men ate together now stands enclosed in glass.

Twice a day a speeding train passes only inches from the homes of this residential neighborhood.

An impressive piece of infrastructure that seems outsized when considering it serves an island with a population of less than 300.

Longest fortress system anywhere in Europe.

When Croatia became independent of Yugoslavia, the splintering governments left behind these concrete tunnels.

Where the lovelorn find a home for their sentimental keepsakes.

Houses are tucked between, on, and underneath giant boulders.

A collision of human error and natural geothermal pressure created this rainbow-colored geologic wonder.

At 22 feet tall, these Bronze Age monoliths are some of the tallest standing stones in the United Kingdom.

Led Zeppelin wrote some of their most iconic songs at this little 18th-century Welsh cottage.

This rare surviving broch is one of Scotland's most impressive Bronze Age structures.

The pretty iron lamp is a reminder of the architecture underneath London's streets.

Once the most densely populated place in the world, this island is now a ghost town.

This imprint of an old computer keyboard has a unique backstory.

This lab's maddening silence is good for business but bad for sanity.

One of the world's largest pyramids stands within El Mirador, the "lost city of the Maya."

This 1776 beacon on the coast of Wales is said to have a ghost called Raymond, the last lighthouse keeper.

The wreck of a B-29 Superfortress now stands as a memorial left in the moors.

A modest stone circle in North Wales.

Where a railroad loops under or over itself to rise or drop more than 70 feet in a short distance.

Spend the night in this formerly abandoned traditional Scottish village.

This isolated island is often capped by its own fluffy cloud.