San Marco Basilica
There is no place like Venice.  Sometimes it gets a bad name for being crowded and touristy, but it is still a wonderful place to go.  This is one of the most beautiful, yet gaudy, churches I have been to.  It is beautiful on the outside, stunning on the inside.  The aerial views are from the neighboring Campanile, a bell tower free standing next to the church.  This Byzantine-Oriental basilica replaces an earlier chapel as was started in the 11th century.