Dr. Kathy Sullivan, a 68-year-old astronaut and oceanographer, became the first person to both walk in space and reach the deepest known spot in the ocean on Monday, June 8th.

In October of 1984, Sullivan walked in space, the first American woman to do so. Thirty-six years later, she became the first woman to take the a 35,810-foot dive to the Challenger Deep.

Sullivan is the first person to reach space and the Challenger Deep, and is one of only eight people to ever reach the Challenger Deep, located in the Mariana Trench about 200 miles southwest of Guam.

After their nearly seven-mile journey down the trench in the Limiting Factor—the only submarine in the world that can reach the Challenger Deep—Sullivan and fellow explorer Victor L. Vescovo spent about an hour-and-a-half collecting images. Then came the four-hour ascent to the surface.

Once back on their research vessel, Sullivan called a group of astronauts on the International Space Station (ISS) to share what she’d seen.

“As a hybrid oceanographer and astronaut, this was an extraordinary day, a once-in-a-lifetime day, seeing the moonscape of the Challenger Deep and then comparing notes with my colleagues on the ISS about our remarkable reusable inner-space outer-spacecraft,” Dr. Sullivan says in a statement released by EYOS Expeditions, a company that helped coordinate the mission.

Sullivan reflected on the difference between the two extremes in an interview with The Times.

"If you're looking for that absolutely glorious picture postcard view, space wins it every time,” she says. “But if you want to be dazzled beyond anything you can imagine about the variety and abundance of life on Earth, go into the sea.”