The modern birthplace of Irish freedom.

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.

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

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."

Over 50 exquisite hand-painted Renaissance maps decorate a Medici storage room.

No telescopes, no power, no gift shop: The Observatory of Chichen Itza, one of the world's oldest observatories, takes astronomy back to basics.

Every equinox this Maya pyramid puts on a spooky ancient light show.

These azure waters were thought to lead to the Mayan Underworld.

Northern Ireland's Brobdingnagian stepping stones.

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

An outstanding and haunting glimpse of the horrors of the Great Famine of Ireland.

Giant topiary dog once played a role in a terrorist bomb plot.

Of course Salvador Dalí lived in a castle...

A beautiful but toxic fountain of mercury.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

Milan's duomo is covered in beautiful carving including a curious "dinosaur-like" beast.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

A centuries old castle atop a dormant volcano houses museums devoted to both women and witches.

Monsters and miniatures are held in equal esteem at this wondrous museum.

A colorful piece of contemporary art cheerfully clashes with Lyon's historical architecture.

Moscow's most popular cemetery includes the graves of numerous cosmonauts.

Moscow's imposing monument to the Space Age.

World's largest bell sits on the grounds of the Kremlin in Moscow.