St Peter's Basilica

Longer than two football pitches set end to end, Roman Catholicism’s most holy place of worship is perhaps a little over-the-top in its sheer scale and ambition. But for this very reason it deserves to be seen, and the atmosphere really is unlike that of any other church in Christendom: visitors are dwarfed by giant columns and lost amidst the acres of intricately inlaid marble flooring.

Amidst all this grandeur, the human touches – like Michelangelo’s moving 'Pietà' sculpture (1499) of Mary cradling the body of her dead son in her lap – come as something of a relief.

It’s well worth climbing the dome for the extraordinary 360° view from the top (you can knock 231 steps off the 551-step climb if you pay the extra 2 euros to get the lift to the terrace at the base of the dome proper).

Bernini’s graceful piazza, with its curved colonades designed to embrace the faithful in the arms of the Mother Church, is one of the world’s great urban open spaces. Note that the “appropriate clothing” rule is taken seriously here: women are not allowed in to the Basilica with uncovered shoulders or mini-skirts, and men should be wearing long trousers or shorts that cover the knees.