The Vatican is closed on Wednesday mornings for papal audiences, which is when Piazza San Pietro is busiest. The Vatican Museum is closed on Sundays, except on the last Sunday of each month when entry is free, however, on these days you can expect to find large crowds. St Peter’s Basilica is open every day, but it may be especially busy on Sundays and special religious days such as Easter. Masses are held in St Peter’s Basilica frequently throughout each day.