The hollow trunk of this 650-year-old tree was used as a hideout by two Jewish brothers during World War II.

This imposing 20th-century castle was abandoned before it was ever completed.

Deep in a Polish forest, this collection of Iron Age megaliths still holds onto many of its ancient secrets.

Polish luminaries and masterful folk art find sanctuary in this unique cemetery.

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

A peculiar family mausoleum built by a German nobleman captivated by the occult.

This man-made mound monument was built out of soil from all across the Polish empire.

Naturally formed rock city in Poland.

This 700-year-old structure is one of the most unique architectural and historic monuments in Gdańsk.

The unsettling remnants of a torn down movie set lies nearby the ruined location of the actual Płaszów Labor Camp.

This uber-quaint Polish village is known for its habit of painting elaborate floral motifs on just about everything.

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

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

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

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

Beneath Kraków Old Town's main square lies a hologram-filled medieval market vampire graveyard wonderland.

Countless stories attempt to explain Poland's mysterious J-shaped trees.

The walls and ceiling of this Polish church are decorated with thousands of skulls, with another 21,000 skeletons just below.

Town of spiritualists and mediums in Florida.

This museum houses two of Mexico's most impressive Aztec monoliths.

This French cemetery houses some of the most exquisite examples of funerary art in Mexico City.

The ruins of the bathhouse used by the ill-fated last Aztec emperor still lie in Chapultepec Park.

This ancient jade mask depicting the Zapotec bat god was found in the ruins of the pyramids of Monte Alban.

A barbarous band of serpents guard the bases of these Aztec temples.