They waited for hours for the fountain, made famous by a scene in Federico Fellini's ‘La Dolce Vita' in which the late Anita Ekberg wades through its emerald waters, to spring back to life, whiling away the time by taking photos with their iPads and smartphones gripped onto selfie-sticks.
“It's so beautiful,” Laney Farrell, an Australian who daringly perched herself on some scaffolding outside a nearby building to get a better view, told The Local.
“We're only here for two days and it was by chance we came by today and were told the water was being turned back on – it's been worth the wait. Rome is an amazing place, we love all the history.”
Tourists have spent the past 17 months catching glimpses of bits of the nearly 300-year-old monument from a special walkway put over the fountain while repair work was carried out.
The basin was drained with water, taking away the opportunity for tourists to throw a coin in over their shoulder – a tradition which is said to ensure a return to the Eternal City.
“I'll definitely try and throw a coin in, if I can get through the crowd!” Laurie, from the US, said.
“This is my first time to Rome and we leave tomorrow, so I'm very happy to see it and will definitely wish for a return – as well as happiness and good health.”
But Italians were notably absent from the throng.
“Romans rarely come into the centre,” the owner of the nearby Al Picchio restaurant said.
“It's too much hassle to park and too crowded, but some might come by when it's quieter to take a look - they'll especially be interested to see such a feat for Italy - a job done in less than 18 months.”
Calogero, originally from Catania, said he popped by because his office is nearby.
“We're here to steal the coins,” he joked, referring to the late Roberto Cercellata, the Italian who famously raided the fountain of its coins for 34 years.
Cercelletta, better known as D'Artagnan, scooped them up with a long, sword-like magnet. He worked six days a week, under early morning darkness, sometimes raking in almost €1,000 a day.
Police turned a blind eye until the Italian media reported that the Trevi's treasure was being fleeced instead of being used for what it was intended: charity.
That put paid to Cercellata's early morning raids, and he was arrested in 2002. He died at his home in the capital in late 2013.
The fountain, commissioned by Pope Clement XII in 1730, is the end point of one of the aqueducts that supplied ancient Rome with water and was last restored 23 years ago.
The Acqua Vergine runs for a total of 20 kilometres and ends up in the fountain, where tourists can drink it from a special tap tucked away at one side of the monument.
Legend has it the water source was discovered in 19BC by thirsty Roman soldiers guided to the site by a young virgin - hence the name, Virgin Waters.
The tradition of throwing coins into the fountain was made famous by Frank Sinatra's rendition of 'Three Coins in the Fountain' in the 1954 romantic comedy film of the same name.