The lowest point on our planet is the Mariana Trench.

An excerpt from the article 25 facts about Earth

The depth of the trench located in the Pacific Ocean at its lowest point is 10.924 m below sea level. The immersion record in the Mariana Trench was set on March 26, 2012, by director James Cameron, who descended to a depth of 10.898 meters on board the one-man submersible "Deepsea Challenger".