This extraordinary geological oddity resembles human-made pavement.

Relics of Australia's convict past, and a modern scene of unimaginable horror.

It's said that visitors can "see" Tasmania inside this cave.

The holes in the world's longest golf course are in a series of different towns.

A tiny town's spinning, whirling propeller collection holds Australia's largest windmill.

This salt lake was a former mine site and now attracts visitors for its remarkable pink colors.

These oddly shaped pink granite formations got their name after being mistaken for massive piles of hay.

This giant dish located in a sheep paddock was the primary receiver of Apollo 11 TV transmissions.

The oldest operating picture gardens in the world.

The former Nazi Germany concentration camp stands as a museum to remember this dark chapter in European history.

An underground city of salt.

An enormous and lavish Gothic church in Czechia.

A church of bones, decorated with 40,000 human skeletons.

A museum of alchemy and a basement laboratory all housed in an ancient building in a Gothic tower.

1513 Turkish world map, full of European state secrets and snarky commentary.

Legend says if you stick your thumb in the hole and it gets wet, your wish will be granted.

A marvel of Byzantine engineering under the streets of Istanbul.

This remarkably well-preserved Egyptian plinth is pretty well traveled for a giant piece of stone.

An opal mining town in the middle of Australia where people live, worship, and shop underground.

Though it may look like a Modernist cathedral, this structure was built to store massive quantities of grain during World War II.

An incredible garden taking over the interior of a massive sinkhole.

A clear example of the process of erosion in action.

Nine limestone rock stacks on Australia's "Shipwreck Coast."

One of the breathing caves of Australia's Nullarbor Plain.