A marvel of Byzantine engineering under the streets of Istanbul.

Standing atop 2nd-century Roman ruins, this church is one of the oldest and most iconic in Old Cairo.

This unassuming tree stump reportedly traces its roots to the famous pharaoh queen's reign.

This ancient structure is widely thought to be the oldest intact pyramid in the world.

These Egyptian statues have survived for 3,400 years and were an acoustic wonder of the ancient world.

Known as the "Valley of the Moon," this Jordanian wadi is one of the most amazing desertscapes on Earth.

This exceptionally well-preserved ancient marvel also houses a small museum dedicated to Jordanian folk tradition.

The most gigantic, swoony, intimidating trio of fingers in all of antiquity.

Gladiators battle and chariots race daily in the ruins of a once-great Roman city.

An ancient capital city that dates back 3,000 years old and harbors many surprises.

A more chill but no less fascinating version of the famous ancient archeological site.

A new sculpture calls attention to climate change in the centuries-old city it threatens.

The only museum with its curator—and her pets—buried inside.

A copy of the famous statue can be found in this Florence piazza, along with one of the most breathtaking views of the city below.

Decorated by local artists, the city's utility boxes have become three-dimensional canvases.

This natural wonder is disappearing at an alarming rate.

A surviving remnant of the thick ice mass that once mantled most of Western Canada's mountains.

An overlooked memorial honoring the local Washington residents who died in World War I.

Look closely and you’ll notice that the color changes a third of the way up the tower.

Daredevil repair workers can worm their way out the access hatch, loop ropes over the apex and rappel down the monument.

Those with a sharp eye can find the hidden image of a German Shepherd on the memorial's Mural Wall.

Hundreds of lucky felines haunt the ruins where Caesar was murdered.

A home designed to be on the cutting edge of comfortable, low-cost living.

A hidden treasure of an abandoned city lies deep in the jungles of Campeche, Mexico.