St Peter's Cathedral
From Tardis Wiki, the free Doctor Who reference
St Peter's Cathedral, also known as St. Peter's Basilica, was a church located in Vatican City.
The construction of the Basilica began in 1511 but was not completed until November 1626. (AUDIO: Fallen Angels)
In 1968, Jean-Pierre Rex, while under the influence of Om-Tsor, carved his symbol into the floor of the cathedral. According to a 15 March La Stampa article, Pope Paul VI considered this "the most serious of crimes." (PROSE: Revolution Man)