With a B.S. and M.S. in Aeronautics and Astronautics from MIT, Greg Mark started and sold two companies, one of which designed and manufactured high-performance, computer-controlled composite race car wings. He then questioned why 3D printers couldn’t print carbon fiber, and in 2013 he founded Markforged, introducing the world’s first 3D printer that could print in continuous carbon fiber. And he didn’t stop there. In 2017, the company unveiled the Metal X — a system capable of printing in metal. The company now has over 300 employees, with 6 offices worldwide and was ranked the 10th fastest-growing tech company by Deloitte in 2018.