"The most colorful grottoes of the world.

Gardens representing parts of Asia, Europe, and the Mid East are tucked away among the Soviet-style buildings in East Berlin.

An intricate and amazing house built by architect Karl Junker.

Berlin's natural history museum houses the world's largest mounted dinosaur and the late beloved polar bear Knut.

A striking 12th-century-style castle built on the edge of a cliff.

A sprawling Baroque park with 300-year-old hydro-pneumatic waterworks.

This medieval castle overlooking the Elzbach river looks just like it did hundreds of years ago.

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

A collection of biblical memorabilia.

An overgrown and largely forgotten cemetery lies hidden within the outskirts of Amsterdam.

A beautifully eclectic mix of architectural styles.

Cat art as far as the eye can see.

A floating cat sanctuary on an Amsterdam canal.

This memorial museum chronicles the apocalyptic destruction of the First World War.

A collection of weird and wonderful art fills a former houseplant nursery.

This Belgian palace was long the domain of priests and aristocrats but is now being turned into an art commune.

A once-magnificent collegiate church is falling into ruin.

This modern arts center is built around a gem of late-Baroque architecture.

Artwork tucked within the trees greets visitors with surreal sonic experiences.

A magical and peaceful ruined Cistercian abbey in what is now southern Belgium.

This fairytale castle was built as a show of power but was nearly torn down thanks to its history of torture.

Lavish royal estate punctuated with heated greenhouses.

This serene, turquoise lake in an extraordinary nature reserve showcases a rare natural phenomenon.

The first public library in the Americas has more than 45,000 books dating back to the 15th century.