Stalactites and stalagmites in a beautifully lit cave.

Renaissance villa and gardens complete with a tormented colossus.

Thousands of well-dressed mummies below a monastery.

This community on a small Venetian island has taken to painting their houses in bright neon hues.

Pompeii's less famous neighbor is still revealing her secrets.

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

This Venice bookstore has resigned itself to constant flooding by keeping its books in bathtubs and boats.

A submerged archeological park still holds the wonders of a Roman Sodom.

A 16th-century horror show built in a lovely Italian garden.

An Italian crevasse filled with abandoned buildings gives visitors a look at the world without humans.

This Luxembourg cave is covered in cryptic looking marks left by mining activity.

An expansive complex of subterranean tunnels is all that remains of one of Europe's most formidable medieval fortresses.

This tri-part waterfall is a little bit of fairytale beauty in the heart of Luxembourg's Little Switzerland.

This noble mash-up in eastern Luxembourg is part Medieval, part Renaissance, all castle.

Once the local rulers had gone these enchanting ruins housed common folk in an almost real life fairy tale.

A passage grave used in neolithic rituals.

This natural crater along the coast of Jersey may take its name from the devil statues who have watched over it.

These imposing walls and towers look more like the ruins of a fortress than a monastery.

This 5,300-year-old tomb with mysterious carvings crowns an Irish mountain.

This 14th century tower house was once the home of Irish poet W.B. Yeats.

Ireland's most remarkable collection of these curious cone-shaped houses is worth the buzz.

The Grand Lodge of Ireland is one of the oldest in the world, full of fantastical, elaborately themed rooms.

Impressive mining ruins overlook a spectacular view of Ireland's Copper Coast.

Ancient Bronze Age rampart that was used into the middle ages.