What's the main square in Vatican City called?

St. Peter’s Square or Piazza San Pietro is probably one of the world’s most famous squares and one of the most breathtaking. The dimensions of the square are spectacular: 320 meters long and 240 meters wide. In the liturgies and more noticeable events St. Peter's Square has held more than 300,000 people. The construction of the square was carried out between 1656 and 1667 at the hand of Bernini, with the support of Pope Alexander XII.

Source: Civitatis Rome