Its not vatican
According to the Catholic Encyclopedia the Cenacle (the site of the Last Supper) in Jerusalem was the "first Christian church" but Dura-Europos church in Syria is the oldest surviving church building in the world.
Who or what is Rosemary, the stone image carved behind the choir of the 13th-14th century St. Mary's Church in Lübeck, third largest church in Germany?
Which of these is the eastern part of a non-collegiate Christian church, sometimes known as the choir, usually separated from the nave by a screen or railing?
The Vatican erected a statue inside the Vatican's walls of which person who was convicted by the Catholic Church of heresy in 1633 and sentenced to house arrest for life?