Rare recess caves fill this unbelievably beautiful Ohio park.

The world's first hotel built in an abandoned water-filled quarry.

This shop and studio is dedicated to the art of the book, from letterpress to bookbinding.

A once-glowing grotto at the bottom of Waikapalae Wet Cave.

This cluster of little wooden huts once ground local farmers’ wheat into flour during the days of the Austro-Hungarian Empire.

This centuries-old Italian chapel hangs midway down a sheer cliffside.

A massive underwater sinkhole made famous by Jacques Cousteau.

The highest bridge in America was built for an almost unnervingly small amount of money.

This lovely, if imposing, piece of Canadian gothic is possibly the most photographed hotel in the world.

A battle between nature and architecture in the Cambodian jungle.

This small town in the Netherlands has no roads but instead, miles of canals and over 100 bridges.

This neon blue river gets its color from a unique mix of bacteria and volcano minerals.

This picturesque mansion has gone from opulent ruin to nature museum.

Once an opulent Art Nouveau hotspot, the Constanța Casino is one of Romania's most beautiful abandoned buildings.

Construction of Barcelona's iconic (but controversial) church is expected to be completed in 2026—a century after the death of its architect.

A massive Montreal stadium that has seen nothing but trouble since its inception.

A magnificent Victorian garden that brings the charm and style of old-time aristocracy to the 21st century public.

An abandoned castle owned and ignored by Masons carries a cursed history.

An ethereal glowing blue ocean cave in Croatia.

A lovers' beach, tucked below the surface of the island, provides a safe haven for romance.

Three bridges straddle a stream, one stacked upon the other.

A island reachable by a causeway at low tide is possibly one of the earliest Western European locations to be identified in text.

A humid oasis combines recreation with exploration in a unique underwater cavern.

Mother Nature outdoes herself with this stunningly beautiful set of caves carved into marble.