Archaeologists excavating a site in central Rome say they've uncovered what may be oldest known temple from Roman antiquity.
Along the way, they've also discovered how much the early Romans intervened to shape their urban environment.
And the dig has been particularly challenging because the temple lies below the water table.
At the foot Capitoline Hill in the center of Rome, stands the Medieval Sant'Omobono church.
Today, the Tiber River is about a hundred yards away. But when the city was being created, around the 7th century B.C., it flowed close to where the church now stands, where a bend in the river provided a natural harbor for merchant ships.
"And here they decide to create a temple," says Nic Terrenato, who teaches classical archaeology at the University of Michigan and is co-director of the Sant'Omobono excavation project.
"At this point Rome is trading already as far afield as Cyprus, Lebanon, Egypt," he says. "So they build this temple, which is going to be one of the first things the traders see when they pull into the harbor of Rome."
The temple the foundations of which are below the water line was probably dedicated to the goddess Fortuna. The archaeological team discovered large quantities of votive offerings such as miniature versions of drinking vessels, left not by locals but by foreign traders.
In antiquity, Terrenato says, temples built on harbors had the function of fostering mutual trust between locals and traders.
"It's like a free trade zone and the goddess is supposed to guarantee the fairness of the trade," he says.
The discovery of the archaic temple's existence came after years of fundraising in Italy and in the U.S., and it required sophisticated technological know-how.
Last summer, an ambitious joint project of the University of Michigan and Rome archaeology officials finally got under way.
Archaeologist Albert Ammerman, who has excavated numerous sites in Rome, calls it a "mission impossible."
"They're digging at the very bottom of this trench, at about 7 and a half feet below the water," he says.
The team used heavy machinery to drill a rectangular hole 15 feet deep. A crane lowered large sheets of metal to keep back the soggy soil.
Terrenato says the archaeologists had to fight claustrophobia to be able to spend as much as 8 hours a day at the bottom of that trench.
"You're in a very deep hole, and although you know in theory that the sheeting is going to hold everything up, there is a primal part of your brain that tells you to get out of there, if the walls come closing in there's not going to be any way out for you," he says.
The foundations of the temple of Fortuna were visible for only three days for security reasons, the team could not leave the trench open and it had to be filled up again.
But digging through the city's many layers, archaeologists have learned a lot: Early Rome a city of high hills and deep valleys prone to flooding soon became one large landfill as the founders chopped off hilltops, and dumped them into lowlands to try to make the city flatter and drier. And as the city grew layer by layer and more temples were built, Ammerman, the archaeologist says, the Romans encroached on their river, diverting the original waterway.
"It's actually not totally natural, it's the humans are actually changing the river to the way it is here," he says. "They had the ability to realize that to make their city go, they have to transform the landscape."
As they figured how to cope with their surroundings, the early Romans developed sophisticated engineering and administrative skills and a collective ability to deal with their challenging environment.
It's discoveries like these, Ammerman says, that debunk the idealized image of ancient Rome the immutable and eternal city as a place that never changed.