The largest cactus farm in Africa.

This impressive system of tanks was used to store drinking water as long as 2,000 years ago.

Live a night as a Byzantine King, with a minibar and private jacuzzi.

While not Turkey's deepest underground city, this subterranean redoubt is the largest.

The deepest underground city in Turkey was designed to protect 20,000 people behind massive stone doors.

This futuristically sylvan church is a glass-enclosed marvel of modern architecture.

The ruins of a medieval castle linked to the murderous French lord that inspired the famous legend of Bluebeard.

The institution is sitting on a goldmine of 21,000 paints, varnishes, pigments, and primers preserved for posterity.

This giant, 83-year-old ship elevator is an engineering feat to behold.

Iran's colorful terraces are a rare geological masterpiece.

Dead weights honor the dead of Portugal's fishing industry.

It took an artist 20 years to create this sprawling sculpture garden honoring the area's ancient inhabitants.

A mysterious light floating in the trees of Arkansas may be a piezoelectric effect.

The first skyscraper to include a Ferris wheel built into the facade.

This Manchester laundromat is hiding something.

The skulls and bones of thousands of soldiers line the walls of this small Italian chapel.

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

This eclectic, mosaic-clad home includes a bamboo ping-pong loft and a "Whispermaphones" intercom.

A cluster of granite granaries perched on stilts.

This museum in a Paris apartment gives a unique look at the iconic French singer's life.

It was originally part of a "terrible lizards" collection at the 1964 New York World’s Fair.

The towering figures were created from the cemetery's fallen old-growth trees.

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

More than 5,000 artifacts donated by the people of the city, plus a room entirely devoted to the band U2.