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.

A remarkable two-country morph, this town is part of Germany legally but is by all other measures Swiss.

See the rare bloom of the "Queen of the Night" cactus at one of the world's largest succulent collections.

The only place where can you share a seat with the bums of the Fab Four.

These stones mark 200 years of friendship between Britain and France following the Napoleonic Wars.

Overlooking the spot where the Pilgrims boarded the Mayflower stands Devon's answer to the Colossus of Rhodes.

This ancient stone bridge dates back to the early Middle Ages.

This tangled English forest looks like something right out of a fairytale.

This no man's land slicing through the island is strewn with abandoned relics of another time.

Fortified homes of highland warriors that are still in use today.

The decaying remains of a once-luxurious Soviet spa town.

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

The cave holds a spectacular array of stalactites and stalagmites, including one shaped like a giant human heart.

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