The Field Cathedral of the Polish Army is the main garrison church of Warsaw and the representative cathedral of the entire Polish Army. In the past the church served a variety of communities and roles: it used to be the church of the Collegium Nobilium and in the 19th century was also turned into a Russian Orthodox church. Currently all major military religious feasts in Warsaw are held there.
It is located on Długa Street 13/15, opposite the Heroes of the Warsaw Uprising Monument and Krasiński Square, close to Warsaw's Old Town.
Wikipedia https://en.wikipedia.org/wiki/Field_Cathedral_of_the_Polish_Army
Address 13/15 Długa, Warszawa 00-238, Poland
Coordinates 52°14'55.909" N 21°0'25.145" E