Churches are always free. The ones in St. Augustine are just spectacular!
There is a Greek Orthodox Shrine. The Byzantine art and icons were particularly interesting to me.
The Memorial Presbyterian Church was huge for a Presbyterian church. It looked more Catholic. The rich Henry Flagler (founder of Standard Oil and the Florida East Coast Railway) built the church as a memorial for his daughter. He, his first wife, his daughter and grandchild are in the mausoleum here.