Advanced LIGO, a 2nd generation gravitational wave detector is expected to observe binary mergers out to cosmological distances. It is currently being installed at the LIGO observatories in Louisiana and Washington State. I will discuss the technology required to make Advanced LIGO work and give an update on the installation status. Then I'll explore the science case for a successor of Advanced LIGO. I'll look at the technology required to achieve the exquisite displacement sensitivity required to listen even deeper into the cosmos.