The fountain marks the area where hundreds of accused witches were burned at the stake.

A book bound in the skin of an infamous criminal, along with countless other specimens.

A 18th century graveyard and its astonishing cortege of macabre iconography.

This series of Scottish caves has no clear purpose other than baffling historians.

Tiny effigies of the victims of Edinburgh's famous Anatomy Murders.

An extensive collection of reliquaries containing the bones of saints housed in the largest Catholic church in Venice.

Venice's "Island of the Mad."

A small island less than half a mile from Venice is a forbidden island with a dark and twisted past.

On the Irish coast, 18 members of the Howard family are eternally resting in an Egyptian pyramid.

Though they've since been renamed, these two streets hint at Dublin's darker days.

The 19th-century pharmacy (now a used bookstore) was featured in James Joyce’s "Ulysses," and has changed very little to this day.

Oliver Cromwell once seized the land under this house, which included the ruins of a medieval abbey that the owner used to build his stately home.

A collection of housewares from recent Irish history adjoined by a tower from ancient Irish history.

The remains of this deep, dark mine have left behind a haunting rocky warren of tunnels.

Achill's most recently abandoned village dates back to to the Age of Enlightenment.

A nun spent 16 years painting the stunning Celtic mural that covers the interior of this WWI memorial.

The oldest licensed distillery in Ireland.

Just a few miles off the western coast of Ireland lies an isle steeped in Irish literary history.

The enchanting archway is the only surviving portal into Dublin's lost medieval wall.

After being destroyed by IRA sympathizers, the ruins of this stately Irish manor have sat vacant for decades.

Huge standing stones mark a site of megalithic mystery.

Once the longest bridge in Ireland, this rusting span sits abandoned and overrun by nature.

An 1814 castle that hosts an exhibit of "explorabilia".

The world's toughest modern Christian pilgrimage leads directly to the gates of Hell.