Vatican City packs Saint Peter's Basilica, the Sistine Chapel, and the Vatican Museums' 70,000-piece collection into 0.49 square kilometres, the world's smallest sovereign state.
Easter Mass brings hundreds of thousands to Saint Peter's Square, and the Vatican Gardens' Wednesday tour pleasant in spring with Saint Peter's dome at peak photogenic.
Rome hits 35°C and the Vatican Museum queues become punishing without timed entry, but evening Saint Peter's Square at sunset remains memorable.
Cooler weather, queues marginally shorter, and the Vatican Museums at their most pleasant for the Sistine Chapel and Raphael Rooms.
Christmas Mass on December 24 fills Saint Peter's Basilica, the Vatican Christmas tree in the square, and the museums quiet from January through Lent.