St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

This Nazi ruin was the site where Hitler was almost blown up by a suitcase bomb.

This Polish cave has housed a dragon, a brothel, and an enduring legend.

The former Nazi concentration camp stands as a museum to remember this dark chapter in European history.

Real bones which are said to have belonged to a Polish dragon.

An underground city of salt.

A beautiful and moving memorial set on a little island in the middle of the river in Minsk.

A symbolic graveyard for the villages that perished during the Nazi invasion of Belarus.

A striking Soviet memorial commemorates the liberation of Belarus from the Nazis.

Remnants of the city's Soviet history hover over this modern fast-food outlet.

Glowing orb in Minsk houses 8,600,000 items.

Thanks to its heroic service during WWII this Soviet castle has been turned into a monument towered over by a brutalist titan.

A magical sinkhole on the Yucatán Peninsula is adorned with mini waterfalls and hanging vines.

Clap your hands at the base of the pyramid, and the song of a sacred Mayan bird will echo through the air.

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.

A small collection of iguana-infested ruins hides amid Cancún's bustling hotel zone.

Spain's unique Mosque-Cathedral has been a place of worship for both Muslims and Christians throughout its history.

A curious carving hides on a marble column in the Mosque-Cathedral of Córdoba.

"Holy Wisdom" overlooks the city that became its namesake.

A vast Communist-era exhibition space in the Bulgarian capital.

A striking symbol of the Bulgarian capital.

A collection of art from Bulgaria's time as a communist state.

A Bulgarian monument to Russia's role in World War II is constantly being painted in pop culture protest.