Abstract: The BlackGEM telescope array consists of 3 wide-field telescopes, located at ESO La Silla, Chile. Combined they give an instantaneous field of view of 8.1 square degrees. The scientific aim of BlackGEM is the detection of transients as well as ultracompact binaries, as gravitational wave sources. The design is focused on finding faint (m>20) transients in the nearby Universe, following LIGO/Virgo gravitational wave triggers. The talk will give an overview of the BlackGEM telescope array, as well as highlight scientific examples from the first year of operations. The talk will also introduce the Time Domain Telescope, which we propose as an initiative for the ESO Expanding Horizons program, as the next big ESO facility starting in 2040. The TDT aims to be a flexible spectroscopic facility, where many (~100) medium-sized (~2m) telescopes are combined to form a large aperture (~20m) telescope that can also be used in a distributed array.