Amidst the bustling streets of Dublin, there is a hushed garden that is dedicated to "All those who gave their lives in the cause of Irish Freedom."

In the fictional world of Kcymaerxthaere, celestial wonders marked a portal to a powerful route of travel at this site in Madrid, Spain.

A whimsical brother of the nearby Fallen Angel statue takes the falling part quite literally.

An eccentric artist's abode in this small Italian town has been transformed into a surreal temple of mosaic madness.

A fascist-era rural village abandoned since the early 1980s.

The oldest-known example of a historic architectural style recognized by UNESCO.

Stuck in the arcade of Casa Isolani are three arrows of mysterious origins.

A diverse collection of wax, bone, papier-maché and mummified relics.

A subterranean ice warehouse that has lain hidden beneath central London for over a century is now open to the public.

This 19th-century pub features stained-glass windows celebrating Victorian-era "champions."

More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.

One of Ireland's most infamous prisons for rebels including men, women and children.

Vienna's underworld of tunnels and subterranean rivers made an iconic appearance in a 1949 Orson Welles film.

A silly medieval mural preserved on the side of a Viennese house.

A neo-Gothic mansion now houses a wunderkammer of analog tech that hits on all the senses.

Collection dedicated to funeral rites, equipment, and mourning rituals of the Viennese.

An Italian hillside ghost town.

An impressive bridge over a ravine also served as an aqueduct.

The mummified heart of a saint lives on in this church—after a brief hiatus when it was stolen.

One of the most popular megalithic sites in Ireland stands as a humbler version of Stonehenge.

Perfectly preserved ancient monastery in an impossibly dramatic location on a rocky island in the Atlantic.

After it was swallowed by a Georgian mansion, this medieval castle remained forgotten for centuries.

Some of the saint's blood and bones are said to reside in Dublin.

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