A castle from the Holy Roman Empire that hosts traveling youth... in its stables.

From Nazi chemicals to the CIA, this architectural marvel has played a fascinating role in German history.

The entrance to this Frankfurt subway station looks like an old tram car crashed into the concrete sidewalk.

Fantastic views and thousands of love locks.

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

A 16th-century Andalusian palace.

The world's largest wooden structure.

Spain's largest bullring offers a unique glimpse at architecture and history.

A lush indoor jungle fills this bustling Madrid transportation hub.

Commonly acknowledged as the only public monument to the Devil himself.

Madrid's romantically ornate crystal palace has been offering shelter to plants and art for over a century.

An ancient Egyptian temple in the middle of Madrid, Spain.

Order cookies baked by cloistered nuns in a 400-year-old monastery.

Dedicated to a young woman who broke gender barriers at the University of Madrid.

This sweet-toothed bear searching for snacks has been a symbol of Madrid for decades.

A stone slab in Madrid marks the point from which the distances of Spain's national roads are measured.

A relic from one of London's worst 19th-century slums.

This incredible stone temple is a monument to death, victory, and fantasy architecture.

A famous big wave from Japan serves as a tribute to the victims of the disastrous Elbe flood.

The “Coin Cabinet of Dresden” houses a collection of over 300,000 numismatic artifacts, one of the largest of its kind in Europe.

This stone amphitheater was once part of Nazi Germany's plan to promote propaganda.

Ruins of a German castle on top of a towering stone pillar.

This Dresden church was purposely rebuilt Protestant after being demolished in World War II.

The largest treasure hoard in Europe is contained in a castle that was bombed out during World War II.