With Feryal Ozel. The Universe presents us with a myriad of extreme objects where our understanding of physical reality is continuously challenged. Do normal nuclei dissolve into quarks and perhaps into other new particles in the cores of neutron stars? What is the boundary between normal matter and a black hole’s infinite energy density, enshrouded by an event horizon? Why are our theories of gravity and quantum mechanics incompatible? The quest for answers continue with the development of new physical laws, Earth-sized telescopes, and an unending joyful journey to the edge of the extreme.