Six rock shelters covered in abstract art created by ancient Ugandan tribes.

Where the White Nile River dramatically cascades between Lake Kyoga and Lake Albert in Uganda.

The home of half the world's population of critically endangered mountain gorillas.

This enigmatic piece of art is a mnemonic device from the early Renaissance.

Five painted skeletons are hiding behind a church in this tiny village in the Italian Alps.

An unusual resting place built into the hill with an amazing view of Lake Como.

The abandoned "Ghost Mansion" was left to decay in the mountains of Northern Italy.

A tower-like theater in the Swiss Alps built to withstand the high winds and avalanches of the mountain pass.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

A church of bones, decorated with 40,000 human skeletons.

An enormous and lavish Gothic church in Czechia.

Underneath the city that invented pilsners are a series of historic tunnels that have been storing beer for centuries.

A medieval setting reimagined into a unique art alley.

The oldest ruins at this castle overlooking Georgia's Terek River Valley date back to the 10th century.

Legend has it that Napoleon Bonaparte fell in love with this Gothic church.

Over time, this castle grew to encompass the entire island.

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

Underground monastery and fortress.

In Zanzibar, a historic 19th-century palace is a reminder of the world's shortest war.

A once-thriving hotel in the Swiss Alps couldn't compete with climate change.

Caves famous for the dragon-slaying saint who lived there.

The gravestone of a famous poet features a fittingly poetic epitaph chosen by the writer himself.

A symbol of friendship between the mountainous regions of Switzerland and Bhutan.

Medieval irrigation channels built into the sides of mountains provided Valais with water for hundreds of years.