The Dome of St. Peters Basilica was planned & executed by Michelangelo. It was however completed by his pupils after his death.
While Michelangelo is known - more for his creations in the Sistene Chapel, the Vatican treasures contain a few more of his exceptional creations. The "Pieta" is another such creation.
As for the shot, I tried as much as I could to come directly under the Centre of the Dome - but could not avoid the Altar and the Pulpit (in Black).