Three hundred years of preserved Spanish colonial history in San Antonio.

The summer home of the largest colony of bats in the world.

A gorgeous garden oasis with winding paths, stone bridges, and a troubling history.

The Hudson River School comes alive at this palatial estate.

A small Second Empire-style building is one of only seven remaining lighthouses on the Hudson River.

A mountaintop space observatory that is certified dark.

This North Carolina grave is the final resting place of the world's most famous conjoined twins.

Conjoined twins Daisy and Violet Hilton were stars of the vaudeville circuit.

This too-low North Carolina railroad trestle is still a notorious big rig executioner.

A museum dedicated to the legacy of Bob Moog and his pioneering synthesizers.

Early Medieval stones sit on display at the beautiful Govan Old Church in Glasgow.

Books bound in human skin and H. P. Lovecraft's letters are among a few of the treasures this library has to offer.

A 19th century library favored by Edgar Allan Poe and H.P. Lovecraft, known by locals as "the Ath."

But did the famous feminist and abolitionist ever really say those iconic four words?

A 18th century graveyard and its astonishing cortege of macabre iconography.

This observatory within Europe's first dark sky park offers stunning views of the night sky.

The discovery of this Neolithic settlement, which contained a Stone Age "cathedral," threw archaeologists for a loop.

A familiar otherworldly creature guards this 12th-century Scottish abbey.

The taxidermy remains of the first mammal ever cloned from an adult cell are on display in Edinburgh.

The oldest (maybe) swimming pool in Iceland is a stunning oasis built into the side of a lush hill.

Burial site of the world's most widely known researcher on the endangered mountain gorilla.