The grand building on this postcard is the Dominican church and monastery in Lviv's Old Town. It was originally built as the Roman Catholic church of Corpus Christi, and today serves as the Greek Catholic church of the Holy Eucharist. The Dominican Order first arrived in Lviv during the 13th cent.; the cornerstone for the present day Baroque church was laid in 1749.
Lviv's Old Town was included to the UNESCO World Heritage List in 1998, and there are about fifteen other landmarks being part of it. I have received this postcard for an RR I think, there is no name or any other recognition sign on it...thank you to whoever sent this lovely card :) The blue cancellation is amazing, as are the stamps..!