collaboration

https://en.wikipedia.org/wiki/New_Synagogue_(Pozna%C5%84)

New Synagogue is a synagogue located in Poznań at the corner of 17 Wroniecka Street and Stawna Street, near Rabbi Akiva Eger Square [pl]. It is currently the only freestanding synagogue remaining in Poznań. During the occupation, in 1941, it was converted into an indoor swimming pool for Wehrmacht soldiers; during this renovation, the building was devastated and altered. The synagogue is one of the historical monuments and attractions on the Poznań Royal-Imperial Route tourist trail.