This ancient Irish religious site is covered in ancient carvings, many of which have barely aged.

This Irish show cave is said to have been the site of a Viking massacre that claimed 1,000 lives.

This ancient Irish tower could easily have stood in for Rapunzel's prison.

A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

Housed in an old church, this hunting museum holds a collection of mythical bird-rabbit creatures.

The patron saint of spinsters grasps a container of dried blood.

Go surfing on this urban wave, "hacked" by local surfers.

The oldest continual pilgrimage site in Britain was supposedly created by a gruesome beheading.

A rocky Irish outcropping with a history of wealth, conflict, and ruin.

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

Dublin's "Dead Zoo" serves as a window to Victorian museum design.

The gorgeous library at Trinity College is home to remarkable treasures of Irish identity.

Behemoth, cannon-like telescope operated by generations of Irish earls.

Huge standing stones mark a site of megalithic mystery.

Ancient pueblos built into the base of a natural canyon wall.

Some of the tallest ancient American ruins continue to inspire awe and curiosity.

America's only nuclear missile silo open to the public.

This Arizona observatory is famous for investigations into Martian life, and as the place humans first spotted Pluto.

This 4,000-foot-diameter hole is touted as "the most well known, best preserved meteorite crater on Earth."

A spiritual vortex among the red rocks in Sedona.

An homage to everyone's favorite prehistoric cartoon family.

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

A long abandoned hospital building on the outskirts of NYC.

The remnants of two World's Fairs are here, complete with a 12-story globe, a mini-Manhattan, and a UFO-shaped pavilion.