Vatican City

The Vatican was the central governing body of the Catholic Church. In an alternate timeline caused by the time field, the Pandorica, which was guarded by the Lone Centurion, was donated to the Vatican in 1231. (DW: The Big Bang)

In the 51st century, the religious military force called the Church was commanded by the Vatican. It's unknown if this is the same Vatican or merely reusing the name. (REF: Doctor Who: The Encyclopedia)