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

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

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

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

Unusual building appears to be haphazardly built from randomly piled bricks.

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

You'll find just about anything in this funky Tbilisi flea market.

A wall of chewing gum moonlights as collective art.

The location along the shores of the Great Salt Lake of what was once called, "The Coney Island of the West", now sits barren due to arson and time.

A three-piece musical sculpture installed between the subway tracks at Kendall Station near MIT.

A pair of antique trolleys are on display at one of the oldest subway stations in the United States.

The colonial home of Paul Revere during the American Revolution.

This steep slide at a kids’ playground went viral after an police officer tumbled down it.

Interactive museum complete with costumed re-enactors and the only known surviving chest from the Boston Tea Party.

A memorial to Chinese freedom in the city where American freedom was born.

Created by a local artist, these quirky sculptures each have their own names and personalities.

Macabre headstones carved with winged skulls, dancing skeletons, and pithy reminders of impending death.

19th-century operating theatre in which the use of ether was first demonstrated - plus, a skeleton and a mummy!

The Boston square dedicated to the dark poet who was born nearby.

This grandiose staircase was part of the revival of a medieval Spanish architectural style combining Christian and Islamic influences.

These magnificently sculpted tombs represent Spain's own legendary version of "Romeo and Juliet."

This multi-level, aqueduct-footbridge hybrid is one of the greatest works of the Spanish Renaissance.

A fortified palace in the shape of a ship on the Thiou river.

This medieval synagogue survived the Inquisition as a hospital and church.