This ancient Greek place of assembly and marketplace is being revealed layer by layer below the modern Athens cityscape.

A fake Transylvanian castle houses a cathedral of antlers.

This hidden art nouveau gem was designed by an architect in search of a national style.

Possibly the world's largest hourglass only needs to be reset every New Year's Eve.

From Austrians to Nazis to Soviets, this historic Budapest fortress has a history as complex as the city itself.

Built in 1870 at the bridge that connected Buda and Pest, this spectacular incline railway was almost lost forever during World War II.

This Hungarian castle was built out of cardboard and wood until it proved so popular that it got upgraded to stone.

A trail of iron footwear stands as a monument to the thousands executed along this riverbank during WWII.

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.

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.

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

One of its engravings is believed to be among the first representations of medical and surgical instruments.

The largest known Ancient Egyptian obelisk.

Known as the Sistine Chapel of Egypt, this tomb houses some of the most well-preserved paintings in Egypt.

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.

Ozymandias’ time-keeping temple.

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

Dublin's most modern, visually spectacular bridge is modeled after Ireland's national emblem.

The modern birthplace of Irish freedom.

A labyrinth hides in plain sight at each of the city's 270 Tube stations.

A quiet, semi-secret square with statues of Mahatma Gandhi, Virginia Woolf, and a conscientious objectors stone.