Fantastically decorated underground chambers built in the 1760s.

Man-made cave with enigmatic carvings, some say made by the Knights Templar themselves.

These ruins of Francis Bacon's once-magnificent manor are hidden in the English countryside.

An eccentric 18th century naval officer built a ship's quarterdeck on his roof, the inspiration for Mary Poppins's "Admiral Boom."

This secluded walkway overlooks a magnificently wild London green space.

The first privately owned air raid shelter in Britain, built after a horrifying night of Zeppelin bombings.

According to the Guanches, the aboriginal people of the Canary Islands, the king of evil lives inside this volcano.

Students can borrow artwork from this gallery to display in their own residences.

This striking steel sculpture transforms environmental data into art.

An unlikely connection between a little English town and the most famous brand of American motorcycles.

A clumsy-looking flying locomotive rusts within sight of a busy rail station.

An imposing Omani fortress surrounded by date palm trees.

Nature's water park in the Wadi Bani Awf valley is full of pools flanked with cliffs and natural water slides.

This bazaar is one of the oldest in the Arabian world.

A sinkhole and now a swimming hole, too, full of dazzling turquoise water.

The opulent car collection of an eccentric Sheikh housed in his own private pyramid.

These otherworldly formations were shaped over millions of years by the forces of nature.

The world’s largest LED display, built over an F1 race circuit.

This living legend of maritime history is enjoying a second life.

The cluster of igloo-like domes forms the remains of an ancient burial ground.

The world's largest frame offers spectacular views of the city's past and present.

On any given day this sprawling market houses literally tons of government-regulated gold, gems, and precious metals.

An abandoned desert hamlet swallowed up by sand.

This mysterious abandoned fort looks like something pulled right from Arabian legend.