One of the world's largest model railroads is a mind-boggling achievement.

An ancient Incan convent on Lake Titicaca's Island of the Moon.

A 90-year-old underground water reservoir offers a more industrial kind of tranquility.

This cemetery has graves dating back to the 17th century, including the city's oldest carved tombstone and an ominous cryptogram.

Stay at this storybook estate, featuring Sir Henry Hudson Kitson's masterpiece "Gingerbread House."

These eerie outliers of the lightning bug family glow a mysterious blue color.

A 150-square-foot masterpiece of American landscape art is the crown jewel of this library and art gallery in Vermont.

A New England curiosity cabinet, one hundred years on.

This three-chambered cave is the only protected natural bat hibernaculum in Quebec.

Is there such thing as too many fruit bats? Not anymore.

Thousands of bats stream out of caves every night on the edge on Thailand's second largest park.

This abandoned railroad tunnel is now home to a micro-colony of bats and a ghost train.

This cavernous swimming spot doubles as a home to the largest known colony of bats in Central Asia.

This Roman quarry once held secret masses and smuggler's contraband and is now home to rare species of bats.

A well-studied colony of endangered bats roosts in this abandoned Victorian Gothic mansion.

Take a hidden path to the mouth of the cave to watch millions of bats swarm at sunset.

These flying foxes dangle from the trees around the library like fuzzy black fruit.

Abandoned railroad tunnel is home to a colony of three million Mexican free-tail bats.

An unfinished rail tunnel that has since been used to house cheese and bats.

The world's largest occupied bat houses hold hundreds of thousands of flying mammals.

Thriving meadows span a rooftop in one of Brooklyn's most heavily industrialized neighborhoods.

This large cave is a summer home to thousands of bats and has a rich history dating back to prehistoric times.

This unique tower has been home to malaria-fighting bats for 100 years.

Each summer, the migratory bats living beneath the bypass form "batnadoes" at dusk.