The remains of Martha, the last known passenger pigeon, serve as a tool to educate about conservation.

This mosaic dedicated to John Lennon was tended for years by a Beatles super-fan.

A pedestrian island in the middle of world-famous Times Square emits a strange (and purposeful) humming noise.

This historic address is home to the beloved ball and is an almost totally empty building among the most expensive real estate in the world.

Whisper secrets in a busy station only to be heard on the other side of this acoustic arch.

A three-story copper skybridge connects two Manhattan buildings with Art Deco luxury.

A popular European tradition makes its way to the states on one of America's most famous bridges.

Each time a baby is born in Ghent, these streetlights flash in silent celebration.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Christ's blood allegedly preserved in a Belgian town.

1513 Turkish world map, full of European state secrets and snarky commentary.

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.

2300-year-old Roman road connecting the empire.

The yawning maw of this pagan visage is said to bite off the hands of liars.

Ancient snack bar of the Roman Empire re-opened.

The last moments of the ill-fated Pompeiians, frozen forever in plaster.

The bomb-ravaged remains of of a colossal Neptune.

A lover's walk between hilltop towns, decorated with graffiti love notes.

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

One of Antoni Gaudí's most classic buildings is well-known for its "dragon-back" design.

Construction of Barcelona’s iconic (but controversial) church was finally completed in 2026—a century after the death of its architect.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.