The oldest surviving mosque in the UAE has mysterious origins and unusual architecture.

This beautifully restored fortification kept the city safe for centuries.

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

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

An imposing Omani fortress surrounded by date palm trees.

This spectacular mosque houses the second-largest chandelier in the world.

A unique museum dedicated to culture and artistry of carpet weaving.

A gigantic collection of teeny, tiny books.

This mysterious but iconic tapered tower appears in many Azeri fairytales and legends.

The building's fluid, wavelike walls are a true feat of architectural ingenuity.

A shrine of fire worship built on top of a natural flame.

Mysterious hillside with a continuously burning natural fire.

Take respite inside this jaw-dropping church while climbing the volcano where Georgia's Prometheus was once chained.

A cylinder monument with a spectacular vista commemorates a friendship that some say never existed.

Abandoned museum from the last days of Soviet domination, with a unique Brutalist design.

The last standing example of an ancient district's teatime tradition.

At this rare mosque in Tbilisi, Sunni and Shia Muslims pray side by side.

A cluster of historic bathhouses built on the famed hot springs that gave the Georgian capital its name.

You'll find just about anything in this funky Tbilisi flea market.

A lively circle of dancers in the Georgian capital commemorates an ancient rite of spring.

With over 10,000 lights, this engineering marvel lights up the city after dark.

The charmingly disheveled clock tower of Tbilisi's puppet theater.

This former luxury resort in Kaua'i is now an abandoned relic.

Babe Ruth and others planted saplings for a 1930s tourism campaign. The saplings grew as the area faded.