An Antoni Gaudí masterpiece in Astorga.

With over 10,000 lights, this engineering marvel lights up the city after dark.

This extraordinary, multi-pillared monument depicts the fascinating history of Georgia.

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

Monks in the empyreal Alazani River valley have preserved their 1,000-year-old winemaking tradition.

This architecturally eclectic fortress witnessed centuries of bloody turmoil, including the massacre of its ruling clan.

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

A small but hugely whimsical theater where marionettes play out the "The Battle of Stalingrad."

This neon lit Georgian cave claims to hold the boulder Prometheus was chained to.

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

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

Ancient rock-hewn town that witnessed key events of Georgian history.

Underground monastery and fortress.

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

Small church on top of a huge rock column.

The Cathedral of Salamanca has a number of unusual carvings but none so surprising as a modern astronaut.

The facade of this 16th-century building is decorated with carvings of 300 seashells.

This castle has links to Portugal’s founding and struggles for independence.

A stunning 18th-century site where pilgrims ascend by a series of punishing stairs only to return via funicular.

Controversially restored in the 1970s, this giant 15th-century mosque is shrouded in legend.

Home to what was once considered the largest gate in central Asia.

Where Stoddart and Connolly suffered in the infamous Bug Pit.

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

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