A sacred well steeped in Pagan roots on the West Coast of Ireland.

Belfast's namesake river still winds below the city center, hidden from sight.

Another entry into the world of Edinburgh's pop-up artworks.

One of Edinburgh's oldest pubs hides a 19th-century skittles alley in the back.

A poetic monument to the Scottish Parliament.

The mummified heart of Louis XVII, the lost dauphin of the French Revolution.

A striking glass tribute to two sisters who suffered during Scotland's "Killing Time."

A 19th-century time capsule of travel, fiction, and historic texts still available to the public.

This working class sculpture pounds his hammer all the livelong day.

A beautiful final resting place for some of the noteworthy deceased.

This nondescript building hides an entrance to an underground nuclear tunnel system.

An abandoned canal route lies hidden under the streets of Manchester.

Manchester salvaged this sculpture of the adopted Mancunian when it was no longer wanted in Ukraine.

Manchester's abandoned train depot lingers in a post-industrial purgatory.

Hidden on the urban banks of a Manchester river are a series of abandoned waterside industrial sites.

A tiny, hidden alleyway dedicated to the father of meteorology.

A Lovecraftian altar of nightmarish bronze chairs sits ominously on a boardwalk in Puerto Vallarta.

The ruins of the second of three churches dedicated to the saint in a touristic Scottish town.

One of the few remaining ancient aqueducts described by Frontinus as 'the most solemn testimony of the Empire.'

Originally used to sell brandy, the bull-shaped billboard became an iconic symbol of Spain.

The remnants of a depressing public toilet are now a hub of ever evolving street art.

A tiny, heartwarming piece of art hiding in plain sight.

These lovely Turkish-styled baths were brought back to life after winning a reality show competition.

19th century museum with an eclectic mix of curiosities, from Egyptian artifacts to items on archery history to the skull of the world's oldest horse.