The secret city built by the Manhattan Project.

One of the Cemestos prefab homes built to secretly house thousands of Manhattan Project workers.

John Hendrix predicted the creation of the "Secret City" built as part of the Manhattan Project.

This hotel was used during the Manhattan Project to house official visitors.

The second-oldest garden cemetery in the U.S. was also a college brainstorm spot of Stephen King.

An obelisk marks the spot where a British explorer's heart was buried before the rest of his body was transported to England.

The world's highest and most dangerous infinity pool lies at the precipice of Victoria Falls.

The stunningly blue waters of these beautiful caves also have a violent past.

Once a meeting point for Swahili slave traders, this ancient tree is now a monument to those killed by the slave trade.

Artifacts showcasing the witchy history of Zambia.

Zambia's smallest national park is home to one of the world's largest annual mammal migrations.

Behold, a collection dedicated to Germany's favorite vegetable.

The prison where Hitler wrote "Mein Kampf," and 278 Nazis were later executed for war crimes.

A Neolithic burial site erected around 3000 BC.