Here's why:

* Striated with canals: While the "canals" on Mars were once thought to be artificial waterways, we now know they are actually natural geological features, like valleys and canyons. These features often appear as linear markings, giving the impression of canals.

* Four inactive volcanoes: Mars is home to the largest volcanoes in the solar system, including Olympus Mons, which is three times taller than Mount Everest. While these volcanoes are inactive, there's evidence that they were once very active.

Let me know if you have any other planetary riddles!