Near Birmingham, England three and a half miles of top-secret tunnels housed a World War II “shadow factory” and a Cold War nuclear bunker.

A medieval device used to punish and shame wrongdoers still hangs outside the village church.

A hidden tunnel leads to a medieval queen's shrine buried beneath a parking lot.

The half-finished remains of what would have been Scotland’s biggest piece of landscape art.

This Norman church survived the Reformation before suffering 300 years of neglect.

A house of bones — but nobody is quite sure to whom they belong.

A lasting remnant of The Blitz.

On the outskirts of Edinburgh, a trio of topiary created by one man over the course of more than 20 years.

Long abandoned underground complex to keep royals safe from a nuclear war that never came.

A memorial commemorating the only Scottish police investigation into an extraterrestrial incident.

A once extravagant mansion, now reduced to ruin.

This mountain is one of the largest in Scotland but is better known for its hollow insides.

Believed to be the smallest castle in Europe.

A beautiful and abandoned New York subway station from 1904, complete with chandelier.

Scotland is filled with standing stones that date back hundreds or thousands of years. This is not one of them.

As part of an 800-year-old tradition, a man parades through town covered in a suit made out of spiky burrs.

A trio of giant megalithic stones in the middle of a golf course.

This tiny little cave was said to have been a refuge for a saint with a glowing arm.

The only fixed chain and post trail in Scotland snakes its way along the base of a towering seaside cliff.

These ancient sea caves hold Britain's highest concentration of Pictish rock carvings.

This beautiful example of Victorian engineering is the oldest water-balanced funicular anywhere in the world.

An abandoned, desolate train tunnel that was used during World War II.

Journey through one of the oldest industrial sites in Scotland.

Visible at low tide, this rusting vessel is one of the last surviving examples of the X-Class "Midget" submarines.