These sand dunes in Iran look like they're straight out of a cartoon - but they're real and insanely dangerous

In the heart of Dasht-e Kavir, a large desert in Iran, there is an enormous area of sand dunes known as Rig-e Jenn. At about 1,400 square miles, it is said to be one of the most impossible areas in the world to pass through.

There are no routes, no trails, no water - just the crazy hills of insanely soft sand. Knowledge of the dunes has come from only the handful of researchers that have dared to explore it, but even caravan travelers in the area avoid this area.

A brave, Danish traveler and photographer, Thomas Flensted, paired up with RO Nature, a team of Iranian safari travel experts, and took on the dangerous challenge of traveling through Rig-e Jenn. Here's what their four days of travel were like.