The largest and most theatrical Baroque fountain in Rome, completed in 1762 by Nicola Salvi and depicting Neptune on a shell chariot drawn by sea horses. Immortalised by Fellini in La Dolce Vita. Tradition holds that throwing a coin over your left shoulder with your right hand guarantees a return to Rome.
It is always crowded. Come at 06:00 for the fountain without the crowds, or after dark when it's lit and the atmosphere is better than midday. A modest timed-entry system operates in peak season — check ahead.