Over two-thirds of the world's population of giant tortoises live among this coral formation.

A salty red wasteland in Tanzania is a breeding spot for endangered flamingos.

This picturesque island graveyard is the final resting place of dozens of notorious pirates.

See hundreds of herons and egrets in the heart of the city in this dreamy hidden park.

Stunning ruins of what was once the center of one of the greatest empires in East Africa.

The centuries-old trees lining both sides of this dirt road may become Madagascar's first natural monument.

A historic and oft-filmed prison stands in a Chicago suburb.

What's left of the ruins of the 1893 Columbian Exhibition, or World's Fair, also known as the White City.

This surprising gem is a world-class archeological museum hidden at the University of Chicago.

Assemble a masterpiece at the first and only North American school exclusively dedicated to mosaic art.

This landmark of the Chicago silent film industry may not be in the picture business anymore but it still stands proudly.

This cheerfully-named branch of the Chicago River is the fetid result of years of blood, entrails, and meatpacking waste.

Cemetery featuring rare glass-fronted columbarium.

A little-visited waterfall in an otherworldly landscape.

"X" marks the spot of an echo chamber in the middle of a plaza.

One of the oldest anatomical theaters in the U.S. still in use was once the site of an infamous cadaver riot.

The remnants of a wooden-hulled fleet built and abandoned in WWI, now home to a thriving ecosystem.

Ship skeletons haunt Baltimore's waterways.

A model home in the Medical Examiner's Office in which grisly death scenes are staged to train forensic investigators.

The design of this historic domed church was influenced by Thomas Jefferson and intended as a statement of religious freedom.

A hidden alley in urban Baltimore is a haven for graffiti artists.

It's not hard to see why the historic Peabody Conservatory of Music's library has been described as a "cathedral of books."

The trials and tribulations of marking Poe's grave.

A gothic church spire sits atop this skyscraper, the tallest church in the world.