Go inside to really appreciate this 500-year-old technological masterpiece.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

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

This Yellowstone geyser may not shoot as high as the nearby Old Faithful, but it erupts for considerably longer.

An architect's childhood fantasy treehouse made real.

Around half a million years ago, these magnificent columnar basalt cliffs were formed from cooling lava.

One of Detroit’s oldest blues clubs stands in defiance of the passage of time and the city’s shifting fortunes.

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

This replica medieval European village in the Dominican Republic was built by a Hollywood set designer.

The final resting place of Christopher Columbus - or possibly someone else.

A sharp sculpture made of thousands of pieces of jagged glass.

An ancient octagonal weather station named for the eight Greek gods of wind.

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

A 2,000-year-old computer demonstrates remarkable engineering and astronomical precision.

This famous archeological mystery may be an ancient example of movable type.

A minotaur, a labyrinth, and a dubious restoration pull in visitors from around the world.

Every spring, locals see the shadowy figures of a ghost army of slain Greek soldiers descend upon this ruined fort.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

An ancient system of freshwater caves filled with animal bones, including that of species long-extinct.

The former Naval shipyard is open for exploring - mostly.

A monument to the conquistador became increasingly controversial in the very city that he founded.

The 19th-century vessel floats proudly on Lake Titicaca, but its journey from Britain to the Peruvian altiplano was far from smooth sailing.

On this tiny spot of land in the middle of Lake Titicaca the only ones who do the knitting are the men.