The oldest and smallest cemetery in Paris is only open to the public twice a year.

An small and easily overlooked archaeology museum chock full of Egyptian artifacts.

A charming 17th-century alley is lined with secondhand bookstores and antiquarian shops.

The library houses an incredible collection of some of the world's most impressive books and manuscripts.

These morbid carvings remind churchgoers of the inevitability of death.

This historic building displays the remains of a victim of the devastating 14th-century plague.

This long-hidden space above Westminster Abbey now displays the battle gear of the legendary King Henry V.

The eerie remnants of an ancient forest were hidden under the sand for centuries.

This centuries-old wooden wonder was built in less than a year and is one of Europe's largest timber-framed churches.

This was once a hall in which a 16th-century royal banquet was hosted by King James VI of Scotland.

Folklore says this medieval fortress was plopped atop a portal to hell to trap the demons below.

Mysterious painted skulls in Moravia.

Europe's second largest ossuary wasn't discovered until 2001.

Underneath this small church are 15,000 bones, arranged by an obsessive academic.

This ancient Irish religious site is covered in ancient carvings, many of which have barely aged.

The only structure left with direct ties to the Salem witchcraft trials of 1692.

This is not only one of the oldest collections in Europe, but also possibly the most beautiful.

This gorgeous reading room houses the oldest and largest art history library in the Netherlands.

One of Europe's oldest libraries.

A 19th century artistocrat's mansion, turned into a library, hidden in a modern library.

The unique waterfall in Iceland's south features a backdrop of geometric black lava columns.

The beautiful baroque library of the Hapsburg empire.

This church looks more like a spaceship than a house of worship.

An ancient Scottish rock formation said to be the gravesite of a giant remains ensconced in legend and intrigue.