This German bone house contains the remains of some 20,000 souls.

The second largest monolith in the world was once betrayed by its lover, Ben Aicha.

An architectural relic that survived the hands of time.

This remarkably well-preserved mosque stands amid an 11th-century caravansary.

Five ancient libraries, little changed for centuries, preserve a medieval archive of Quranic lore and civic documents

A geological bull's-eye visible from outer space.

Climb atop one of the world's longest and heaviest trains for an unbelievable journey across the Sahara Desert.

One of the oldest structures in Helsinki is this burrow grave that dates back to the Bronze Age.

Dedicated to the outnumbered Finnish forces who pushed back Soviet forces during the conflict.

Hundreds of signs pointing to the birthplaces of current Helsinki residents form stalactites on the ceiling of the cave-like Kamppi metro station.

The grandest stage for the world's foremost masters of invisible instruments.

This misspelled graffiti reappears every time it is removed.

An incredibly durable timepiece glows beneath shoppers' feet.

In the waters outside Helsinki, a tiny island once used as a military outpost now welcomes visitors.

Atop this electronic store resides a massive fighter jet.

These enormous, stern-faced statues greet visitors with lanterns, and sometimes costumes.

This former hospital was once one of the oldest mental health facilities in Europe.

This church also serves as a lighthouse complete with a beacon.

An encyclopedic collection of mammal penises.

One of the tallest buildings in Iceland, and perhaps, the most visually impressive.

Burial site of the world's most widely known researcher on the endangered mountain gorilla.

This center in the Rwandan capital supports women’s livelihoods while educating visitors about traditional cooking, craft making, and more.

A haunting theme park is slowly being swallowed by the jungle.

Hindu temple of the dead home to hundreds of long-tailed macaques.