Ethiopia's "smoking mountain" is in one of the hottest regions on the planet and is home to two lava lakes.

An otherworldly restaurant perched on the edge of a jagged cliff next to a medieval holy city.

An Ethiopian "Jerusalem" featuring a church hewn out of a single rock.

Kenya’s oldest town is more than 700 years old and home to 6,000 donkeys.

Abandoned city hidden from the world by tropical forest and isolation on the coast of Kenya.

Drink and dine in a coral cave that's at least 120,000 years old.

This colonial fort is an intriguing example of Renaissance military architecture.

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

This rare volcano spews the strangest and (literally) coolest lava in the world.

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

Sitting atop a rock on Michamvi Pingwe beach, this restaurant becomes its own island at high tide.

This sacred, circular cave is lined with pools so clear and still that it's hard to tell where the water begins.

After sunset the heart of Zanzibar's historic Stone Town neighborhood transforms into a culinary playground.

Freddie Mercury's childhood home is now a monument to the iconic Queen rockstar.

This slowly crumbling mansion was home to one of East Africa's richest and most powerful slave traders.

In Zanzibar, a historic 19th-century palace is a reminder of the world's shortest war.

An underground city of salt.

St. Mary's features one of the most spectacularly decorated cathedral interiors in all of Europe.

A cluster of historic bathhouses built on the famed hot springs that gave the Georgian capital its name.

A treasure trove of astronomical, mathematical, and scientific instruments at Cambridge University.

The Cambridge pub where Francis Crick announced that he and James Watson had discovered the DNA double-helix.

A battle between nature and architecture in the Cambodian jungle.

An Amsterdam street lined with antique shops each one dedicated to a different obscure collection.

This 17th-century structure is a beautiful testimony to traditional Persian architecture