Tubing through a cave lit with glowworms is a magical underground experience.

This mosaic-lined medieval church was built by the world's first admiral and still holds mass in ancient Greek.

A wealth of plants and horticultural curiosities fill this charmingly antique museum.

A cramped wooden attic that once housed one of the world's first movie studios.

The largest collection of medicinal plants in Australia is also home to a witch who will show you how to use them.

Built over an abandoned train yard, this hidden gem is full of winding paths and offers gorgeous views of Sydney Harbour.

Australian Lake set aglow by Noctiluca Scintillans.

An abandoned railroad tunnel is now filled with bioluminescent bugs.

A beautiful 19th-century Armenian mansion is preserved above an unassuming cafe.

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

Ottoman-era houses lovingly preserved.

Roman ruins top white travertine terraces formed by ancient hot springs.

In this historic region, homes and churches are carved into ancient volcanic rock formations.

This small museum is basically a time capsule of daily life in the Soviet Union.

The composer did some of his finest work in this country home, including "The Nutcracker."

Inside the world's largest seed bank, WWII botanists elected to starve to death rather than compromise their collection.

Specimens collected by the author of "Lolita" and self-taught lepidopterist are exhibited in his childhood home.

An ever-growing literary collection housed in the apartment where the Russian author penned his final novel.

The coldest city in the world.

Museum design and public transportation meet in this unique Russian train car.

This frozen-in-time summer home outside Moscow provides a look at Russian life in the 1950s.

A remote forest of stone pillars along the Lena river.

Some of the world's only freshwater seals live in one very special lake in Russia.

Its front wall is striped with a menagerie of fantastic beasts and magnificent monsters.