Here's why:

* Valles Marineris is a vast canyon system on Mars, spanning over 4,000 kilometers (2,500 miles) long, which is about ten times longer than the Grand Canyon.

* It's also up to 7 kilometers (4.3 miles) deep, making it four times deeper than the Grand Canyon.

It's truly a massive geological feature and one of the most impressive canyons in our solar system.