The Mariana Trench is about five times longer than the Grand Canyon. During the expedition, O’Brien helped map a mile of the trench. She also collected water samples. And she took videos.
It's hard for most sea creatures to survive here. That's because of the pressure, darkness, and cold temperature. But there is some life. The sub’s cameras showed tiny creatures on the sandy trench floor. They're called bristle worms.
O’Brien’s ocean mission was a success. She became one of only two people to reach Earth’s highest and lowest points. But O’Brien says you don’t need to go far. Anyone can be an explorer.
“All kids have to do is tap into their curiosity and go and explore with an open mind,” she explains.