For recent generations, it was Anita Ekberg who made this fountain famous when she plunged in wearing a strapless black evening dress (and a pair of waders… but you don't notice those) in Federico Fellini's classic La dolce vita. Don't even think about trying it yourself - wading, washing and splashing in fountains are strictly against local bylaws. And unlike the Grand Tourists, you don't want to drink from it either: the sparkling water is full of chlorine (though there's a chlorine-free spout hidden in a bird-bath-shaped affair at the back of the fountain to the right).
It was an altogether different affair in 19 BC, when spring water was transported here by an aqueduct from the eighth mile of the via Collatina, to the east of Rome. The only aqueduct to pass underground along its whole route into the city, it was the sole survivor of barbarian destruction and other horrors of the early Middle Ages (though after centuries of abandonment the flow has considerably diminished from its heyday, when 100,000 cubic metres gushed into Rome each day). In 1570 Pius V restored the conduit but it wasn't until 1732 that Pope Clement XII called for designs for a new mostra - a magnificent fountain to mark the end of the aqueduct. Completed decades later to a design by Nicolò Salvi, the mostra - the Trevi Fountain - immediately became a draw for tourists who drank the prized waters to ensure a return to Rome.
Tucked away in a tiny piazza and almost always surrounded by jostling crowds, the fountain's creamy travertine gleams beneath powerful torrents of water and constant camera flashes. It's a magnificent rococo extravaganza of rearing sea horses, conch-blowing tritons, craggy rocks and flimsy trees, erupting in front of the wall of Palazzo Poli. Nobody can quite remember when the custom started of tossing coins in to the waters (as celebrated in Three Coins in a Fountain, with its Oscar-winning ditty). The city council made such a poor job of collecting the coins that for 30 years a self-appointed collector waded in every morning and saved them the trouble. Now the money goes to the Red Cross.