The recovered bones of martyrs slaughtered during The Terror are on display in this church crypt.

A 14th century bridge built as a fortress, where the devil lurks on one of its towers.

Hundreds of hidden passageways weave through the old quarters of Lyon.

An icy lake tucked among jaw-dropping alpine panoramas.

A cave dwelling that was started by the Celts, expanded by monks, and finished by knights.

Ancient paintings known as the "Sistine Chapel of Cave Art."

Sacked by Vikings, blessed by William the Conqueror, dealt a fatal blow during the French Revolution—these ruins have seen it all.

The water-powered carriages are long gone, but for over a century this funicular railway has been the fastest route to the highest point in Paris.

Medieval museum built over Roman baths that features famous tapestries of a lady and a unicorn.

France's national museum of scientific and industrial instruments.

This museum houses an imposing skeleton army comprised of creatures great and small.

One of the oldest medical collections in Europe focusing on rare surgical instruments.

This 1,300 year old monastery built atop a single rock was once only accessible depending on the whims of the tide.

The vast, legendary catacombs hold secrets much stranger than stacked bones.

This archipelago homestead-turned-museum has remained the same since its last resident, born in 1897, died in 1973.

These lakeside pictographs were some of the first pieces of prehistoric artwork found in Finland.

Fortifications built for a Soviet invasion that never came now sit abandoned in a losing battle against nature.

This disused church, left to the elements of the Arctic Circle's forests is open for exploration.

A beautiful Arctic museum and nature center preserves the culture of the Sámi people.

A small island dotted with old, historic Finnish buildings.

This irregularly shaped sea fortress has defended not one but three different sovereign states.

Architecturally stunning library serves as the hub of Finnish scholarly life and culture.

A subterranean house of worship carved right out of the bedrock.

This isolated structure beckons adventurers with sublime views of the Faroe Islands.