Did you hear about the German priest, rabbi, and imam?
There have been times in the past where a faith has moved into the house of worship of a different faith. For example, mosques in Spain were converted to churches after the Christian conquest. But this is the first time I know of where three faiths have shared the same site. The architectural design incorporates unique space for the church, synagogue and mosque, but they will share common areas.
It makes sense. From a theological standpoint, these three great religions originated from the same part of the world, and there is some commonality; Abraham plays a prominent role in all three. As a practical matter, Berlin is a secular city, so combining fundraising gives the project a better chance at success.
They have a long way to go. But anything that will bring the faithful of all religions together is a worthy goal, especially now.