That was St. Mary’s Basilica.
http://en.wikipedia.org/wiki/St._Mary%27s_Basilica,_Krak%C3%B3w
The service, that is being conducted at the moment is the part of the funeral, that usualy takes place at the grave-site.
The reason is, that only the relatives and the Archbishop of Krakow Cardinal Dziwisz will go to the proper crypt.