NASA's Curiosity rover reaches Mars ridge where water left debris pileup

NASA 's Curiosity Mars rover reaches Mars ridge where water left debris pileup.

Three billion years ago , powerful debris flows carried mud and boulders down the side of a hulking mountain.

Gediz Vallis Ridge was among the last features on the mountain to form, making it one of the youngest geological time capsules Curiosity will see.

Curiosity has been ascending the lower part of Mount Sharp since 2014 .