Time capsule of a museum, in which the Soviet Union remains alive and kicking.

Dedicated to a Bolshevik revolutionary, this museum is a true time capsule of the Soviet era.

This retro, UFO-like structure is a remnant of the Soviet-era circus.

The Avenue of Mausolea is a series of grand palatial tombs.

Controversially restored in the 1970s, this giant 15th-century mosque is shrouded in legend.

An underground world of gorgeous, palatial metro stations designed as a nuclear shelter complex.

This "tower of death" has acted as an observatory, a religious hub, and an executioner's lair.

A 26-foot shark sculpture—a statement about bombs—set off a municipal battle royale.

Hundreds of caves once used to store grains and animal feed.

A shrine-like museum entirely dedicated to soccer superstar Cristiano Ronaldo.

Men in rubber-soled boots serve as your "brakes" on this toboggan ride Hemingway described as "exhilarating."

These small, triangular, colorful houses are a staple of Madeira Island.

Partially collapsed lava tube and cave system complete with concert hall, underground pond, and unique albino crabs.

Visit a surreal landscape so otherworldly NASA actually used it to train the Apollo 17 crew.

This beautifully verdant lagoon is tucked below a massive volcano in a crater atop a black pebble beach.

A stunning example of traditional salt production set against a dramatic volcanic landscape.

The bar where "The Great Train Robbery" was planned was once a nexus of high society and low morals.

Once believed to be a sacred Roman legionary symbol, this bronze figure inspired the 1954 novel 'The Eagle of the Ninth.'

Well-preserved, still-functional sliding wood doors from Ancient Rome can be found in this Vesuvius-stricken house.

Pompeii's less famous neighbor is still revealing her secrets.

Morocco’s modern capital was once a haven for Barbary pirates, who went so far as to establish a republic of their own.

The bright red stripes streaking across the rocks are the star feature at this Icelandic waterfall.

One of the two original gateways into the Kasbah, this gateway is a nesting site for storks.

Deliberately hidden for centuries, the magnificent Saadian Tombs were eventually uncovered in 1917.