This curious, round temple is the oldest still-standing marble building in Rome.

This ancient market is often referred to as the oldest shopping mall in the world.

The Sighignola summit on the Swiss border offers views so breathtaking it's been named one of the most beautiful places in Italy.

One of seven Jewish catacombs in Rome and one of only two open to the public.

This large, circular tomb is the final resting place of the first emperor of Rome.

This beautiful park on the outskirts of Rome protects the ruins of two colossal ancient aqueducts.

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

The runoff from these fiery cliffs sends red water flowing into the sea.

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

Fabulous formations, weird and wonderful wildlife.

This small group of sand dunes manages to pack in a strange rainbow of colors.

Only two of these trees remain in the natural world, found high in the cloud forest of the island of Mauritius.

Nine of the very few concrete ships ever made in the U.S. are beautifully decaying off a Virginia pier.

Crushed coral and crystals give the sand its signature coloration.

Renaissance villa and gardens complete with a tormented colossus.

The doodles of a genius line the walls of a secret room under the Medici Chapel, where they were hidden for nearly 500 years.

The only "Egyptian" pyramid in Europe and the legendary tomb of Remus.

According to the local folklore, the myriad colors of this lake are the result of a lovelorn wizard's blunder.

The closest thing to Mars on Earth.

A desperate final message left by a POW on the run serves as a memorial for himself and the 97 that died with him.

These giant volcano sponges in Antarctica are thought to be the world's oldest living animal, at 15,000 years old.

It's 2 billion years old!

The “Grand Canyon of Maine” is a three-mile gorge full of striking geological features.

The largest earthwork effigy in the world.