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

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

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

An 18-meter-long sarcophagus of a constantly growing dead prophet.

Light still pours into the ruins of this ancient Islamic observatory.

Right beyond the Uzbekistan-Tajikistan border lies the oldest human settlement in Central Asia.

This dark, damp, perilous tunnel is the only passage from north to south Tajikistan.

A building facade covered with the statues of 11 giants of Tajik literature.

The world's second-tallest flagpole stands proud despite dropping rank.

This Soviet statue is based on a piece of propaganda that's been elevated to national myth.

In Kazakhstan, a colorful cathedral with many lives once survived the most powerful earthquake in the region.

This sprawling market is a one-stop shop for traditional Kazakh foods, from mare’s milk to sheep’s head.

Beatlemania is still going strong... at least in Kazakhstan.

Nicknamed Kazakhstan's Grand Canyon, this natural wonder lies east of Almaty near the Chinese border.

This museum is dedicated to one of Russia's greatest explorers.

Built entirely of interlocking pieces, construction of this Chinese Muslim house of worship required zero nails.

This mysterious complex of abandoned yurts and fading murals was meant to be a center of science and spirituality in Kyrgyzstan.

Lonely minaret stump of a destroyed city.

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.

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

A small museum in the Bay of Pigs gives the Cuban perspective on the famously failed U.S. invasion.

Besides being home to cave paintings and pre-Columbian Cuban archaeological remains, you get to take a boat through this stalactite and stalagmite covered cave.

Neo-cave art on the macro scale.