Einstein Telescope, the proposed European third-generation gravitational wave detector, is now included in the ESFRI Roadmap 2021. ESFRI is the European Strategy Forum on Research Infrastructures that aims to develop the scientific integration of Europe and to strengthen its international outreach. One of the ways to achieve this is the ESFRI Roadmap, an updated collection of the most promising research infrastructures, both future and existing, that has always been an important tool to direct efforts and funds, attract bright scientists and create a collaborative network among research infrastructures.
The inclusion of Einstein Telescope in the ESFRI Roadmap is very relevant for gravitational wave science since ET, along with the US project Cosmic Explorer, represents the next generation of ground-based gravitational wave detectors. It will be built underground and with its three 10 km arms and improved technologies it will allow for a greater sensitivity than ever before, and possibly to explore the beginning of our Universe. There are two proposed sites for the construction of Einstein Telescope, one is the Sos Enattos disused mine in Sardinia (Italy) and the other is the Euregio Meuse-Reno region, at the borders of Belgium, Germany and the Netherlands.