An ancient neolithic tomb that only sees the sun twice a year.

A sacred well steeped in Pagan roots on the West Coast of Ireland.

The oldest public library in Ireland.

Experience what life was like in Ireland during the Viking and medieval ages.

The oldest inn in Kilkenny was established by the first convicted witch in Ireland.

The coffin-shaped church was once home to monks who slept in coffins.

This dazzling wooden church was constructed as part of an elaborate peace project after the Thirty Years' War.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

An abandoned football stadium with a tragic past.

A copy of the Statue of Liberty greets visitors to the birthplace of Auguste Bartholdi.

A Christian retreat founded to welcome refugees fleeing from the Nazis during World War II.

One of the most powerful religious centers in the Middle Ages, dubbed the founder of Western monasticism.

One of the largest ochre quarries in the world, hidden in a limestone landscape.

This ancient theater was once the home of fierce gladiatorial battles.

Even France's favorite aquatic son Jacques Cousteau, couldn't get to the bottom of it.

A mechanized clock where a man fights off a dragon, crab, and rooster.

This charming cobbled backstreet is the most Instagramable street in Paris, much to the residents' annoyance.

An elevator into the Baltic Sea.

Hitler's bleak vision of relaxation still stands as a mostly abandoned 10,000-room resort complex.

A long spiraling walkway winds through the woods, and around a copper beech tree at the center.

This historic Art Nouveau townhouse was the former home of the son of a famous chemical inventor and industrialist.

This non-profit theatre in the heart of Brussels is dedicated to hosting independent films.

A fantastical 13th-century fortification sandwiched by a modern hotel in central Brussels.

This modern arts center is built around a gem of late-Baroque architecture.