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

Poland's oldest surviving university building holds a wealth of historic science instruments including some used by Copernicus.

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

A fairytale Gothic castle steeped in Nazi treasure conspiracy theories.

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

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.

An abandoned town is hidden in Great Smoky Mountains National Park.

Labor provided by Great Depression-era programs restored these 25,000 acres in Tennessee.

The small first-floor apartment where the author wrote her Pulitzer Prize-winning book 'Gone with the Wind.'

An odd and heartwarming stone marker enshrines the moment a community saved a farmer's pig that fell in a well.

This memorial to local World War II heroes is slowly being reclaimed by nature.

The sophisticated hydraulic system of the Nazca civilization.

Its tremendous toad is actually a five-story museum and viewing platform.

This 13th century Gothic brick castle is the largest in the world by surface area.

A medieval stronghold rising over the ruins of ancient Roman villas along Rome's southern coast.

These natural cliffs look like they are a part of an old castle complex.

This turn of the century jail once held Charles Manson.

One of the most spectacular bridges in Spain spans a narrow chasm that divides the city of Ronda.

An oasis of shade and color amidst the bustle of the old city.

A 300-year-old tea shop that brought tea to the English people, not to mention the Queen herself.

This jaw-dropping 19th-century bridge uses its reflection to form what appears to be a perfect circle.

The mysterious, fantastical woodland inspiration for "The Lord of the Rings."

The sound of swaying stalks in this stunning grove has been named a governmentally recognized sound.