This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

Ancient barriers wrap around what was once an important stop along the Silk Road.

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

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

Lonely minaret stump of a destroyed city.

Extremely isolated Silk Road caravanserai in the middle of nowhere.

The controversial final resting place of the equally controversial first president of Turkmenistan.

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

Home to nearly a third of the world's mud volcanoes, Azerbaijan is home to a messy, bubbling, and sometimes explosive landscape.

A museum glorifying the life of Stalin, located in the city of his birth.

A cylinder monument with a spectacular vista commemorates a friendship that some say never existed.

Fortified homes of highland warriors that are still in use today.

Take respite inside this jaw-dropping church while climbing the volcano where Georgia's Prometheus was once chained.

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

Underground monastery and fortress.

The most visited pilgrimage site in Armenia once held a saint in a pit for 13 years.

The possible imprisonment of Vlad the Impaler here earned the medieval castle its nickname, "Dracula's Castle."

The prototype for all Nazi concentration camps.

Glasgow’s piece of the patron saint of love.

An angelic, yet demonic-looking figurine presides over one of Glasgow's most ancient streets.

A weird and wonderful collection of items that pique curiosity and haunt nightmares.

Water-themed sculptures guard this unusually square structure.

A striking glass tribute to two sisters who suffered during Scotland's "Killing Time."

A grave marker depicting a body snatching tableau on a 19th-century tombstone.