A striking symbol of the Bulgarian capital.

This ancient theater, restored in the 20th century, lives on as a venue for dramatic and musical performances.

UNESCO-protected ancient burial ground.

A mountain pass in Bulgaria's Balkan Mountains was the site of four historic battles.

A magnificent, glittering building tucked into a tiny Bulgarian mountain town.

The final resting place of soldiers' loyal canine companions.

A six-ton wedding present for the King of the Scots.

The oldest working mechanical clock in the world.

Famously misunderstood wonder of the ancient world

Eighteenth-century home, where Herschel discovered the planet Uranus.

The final resting place of the great navigator, or maybe his brother.

The footprint of a frustrated devil in Munich's Cathedral.

Daily jousts and dancing barrel makers in Munich's mechanical clock.

3,000 market stands in five former Zeppelin hangars.

Flamboyant architecture from the turn of 20th century.

A black cat protests the City Guild in Riga's Old Town.

A memorial to the murdered Jews of Kaunas.

Ever-growing collection of devils in art.

Museum dedicated to "the man who moved the Earth."

A huge wooden clock that is so beautiful its creator was forcibly blinded.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

Real bones which are said to have belonged to a Polish dragon.

Baroque celebration of the end of the Great Plague of Vienna.