Jacques Piccard
Jacques Piccard was a Swiss oceanographer and engineer, known for having developed underwater vehicles for studying ocean currents. In the Challenger Deep, he and Lt. Don Walsh of the United States Navy were the first people to explore the deepest part of the worlds ocean, and the deepest location on the surface of Earths crust, the Mariana Trench, located in the western North Pacific Ocean.
Jacques Piccard was born in Brussels, Belgium to Auguste Piccard, who was himself an adventurer and engineer. Jacques father Auguste twice beat the record for reaching the highest altitude in a balloon, during 19311932. The Piccard family thus had the unique distinction of breaking world records for both the highest flight and the deepest dive.
Source: Wikipedia