One of Australia's largest secondhand bookstores.

The ruins of a medieval monastery built on a perilous slope.

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

These Stalin-era industrial 'death traps' hang lifeless above the city

This hidden gem is bathed in beautiful natural light.

A deadly ancient portal to the underworld.

These tombs were built into the side of a mountain so that ancient angels could reach the dead.

This beautiful train graveyard is one of the largest collections of steam locomotives in the Mediterranean and Europe.

The alleged house of the Virgin Mary is tucked away in a park and nature preserve on Mt. Koressos in Turkey and is holy to both Catholics and Muslims alike.

An ancient passage filled with stalls selling used books, once frequented by Vincent Van Gogh.

Three connected pink triangles memorialize persecuted gays and lesbians throughout history.

This unattributed sculpture in Amsterdam is hiding in plain sight.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.