A late 4th-century BC archaeological wonder located just outside the suburbs of Thessaloniki, Greece.

Amsterdam's narrowest house facade is a monument to 17th-century tax evasion.

This ancient structure appears Roman, but was constructed during the 16th century and was utilized until 1911.

These public toilets also provide entertainment for visitors to Amsterdam’s Red Light District.

Some 80,000 Delft Blue tiles line the inside of this Amsterdam walkway.

An abandoned Byzantine fortress and notorious prison.

This open air archeological site houses almost as much wildlife as it does classical religious artifacts.

Dedicated to the god Dionysus, this theatre was used for both musical and theatrical performances.

An 11th-century runestone decorates the halls of Terminal 2 of this Scandinavian travel hub.

Frequent fliers welcome in this airplane hotel.

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

One of the world's first dedicated bank buildings in the world is now the oldest one.

This small museum nestled inside a souvenir shop is dedicated to Sweden's most well-known toy.

Several cannonballs of mysterious origins decorate two buildings in Stortoget's main square.

It is said that each of the white stones in the red facade of this medieval house represents the head of a murdered Swedish noble.

An ancient Viking runestone hidden in plain view in Stockholm's old town.

This homeless brass fox tugs at your heartstrings from the foot of a Stockholm bridge.

A mammoth WWII anti-air defense tower has been repurposed as a hotel with a rooftop garden.

Swirling layers of white and red rock earned these mountains their festive nickname.

Foreign invaders almost left this lovely Caucasus palace alone—almost.

A unique museum dedicated to culture and artistry of carpet weaving.

A shrine of fire worship built on top of a natural flame.

Mysterious hillside with a continuously burning natural fire.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.