Light still pours into the ruins of this ancient Islamic observatory.

The Avenue of Mausolea is a series of grand palatial tombs.

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

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

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

This little medieval church hidden in the center of Yerevan was lost and rediscovered—twice.

This ancient monastery complex was transformed from an island to a peninsula when the lake was partially drained.

This Armenian monastery was carved out of cliffs and named after the spear used to stab Jesus.

A geological oddity topped with a 2,000-year-old pagan temple.

At this rare mosque in Tbilisi, Sunni and Shia Muslims pray side by side.

A cluster of historic bathhouses built on the famed hot springs that gave the Georgian capital its name.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

This Arabesque Italian castle was built with a primitive, if ingenious, air-conditioning system.

Every inch of this chapel is covered in craftsmanship from across the world.

Behind medieval walls in a corner of bustling Palermo is a breathtaking former mosque once inhabited by a wolf-taming hermit.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

A musical instrument played by the sea.

Psychoanalyst Carl Jung reported a paranormal experience after visiting this mosaic-lined Roman baptistry.

Filled with goldfish swimming in a shallow pool of sea water, this ancient crypt is more wishing well than burial site.

This 6th-century church has the largest and best-preserved collection of Byzantine mosaics outside Constantinople.

Italian poet Dante Alighieri is entombed in this small mausoleum in Ravenna, and his hometown of Florence has never been too happy about it.

An incredible mosaic-lined monument said to have held the remains of an ancient Roman empress.

A medieval, mosaic-lined baptistry built by a heretical Christian sect.

The roof of this ancient mausoleum is made from a single Istrian stone weighing a massive 230 tons.