The Guardian of Tallinn.

Only a fragment of this 15th-century Dance of Death survives today.

A decommissioned submarine base makes a great space for graffiti art.

Known as the "Valley of the Moon," this Jordanian wadi is one of the most amazing desertscapes on Earth.

A more chill but no less fascinating version of the famous ancient archeological site.

An ancient capital city that dates back 3,000 years and harbors many surprises.

Danish tourist destination well known for open stalls where vendors sell marijuana on the street.

The de facto symbol of Copenhagen is this bronze fairytale which cannot seem to keep its head for very long.

Dine on food tied to Viking history and legend at this subterranean Stockholm spot.

It houses the remains of a 17th-century version of the Titanic.

An illuminated manuscript comprising the life's work of a lone monk, inexplicably decorated with a portrait of Satan himself.

A deer-headed statue that brings together a 12th-century legend and big wave surfing.

This abandoned five-star hotel is now a five-star urban exploration destination.

An ancient and majestic fortress that played an integral role in Portugal's road to independence.

This Industrial Age architectural and engineering gem helps visitors and residents alike traverse Lisbon, “The City of Seven Hills.”

A king's pet, a pope's gift, an artist's inspiration, and a tragic shipwreck.

This unreal Portuguese palace looks as though it's made from a pile of different castles.

A 16th century chapel decorated with bones, skulls, and entire bodies hanging from the wall.

Legacy of the earthquake that nearly wiped Lisbon off the face of the Earth.

One of the most beautiful bookstores in the world hides a neo-Gothic interior behind an art nouveau facade.

This eccentrically decorated palace is replete with grottoes, fountains, tunnels, and caves.

Spanish architects used seized Muslim gravestones to rebuild parts of the fortress.

This magnificent castle grew from a small Moorish fortress, and reportedly inspired two iconic Disney castles.

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