Parts of the Mariana Trench in the Pacific Ocean are up to 11 kilometres deep, so we know little about what sea life there is.
So a team has been sending down a robotic submarine called Deep Discoverer with a camera on it.
Science fans or anyone who is just curious can check out what the camera is showing online.
The three-month expedition is looking for things like fish, mud volcanoes and deep sea coral.
So far they've spotted shrimp, jellyfish and black pillow lava from an underwater eruption.
Scientists are exploring the deepest place on Earth - and streaming live video from there.