Tiber

The Tiber River is a river that, according to legend, the city of Rome was founded on.

History
Romulus and Remus were abandoned on the shores of the Tiber River and were adopted by the wolf Lupa. Romulus and Remus would later build the city of Rome on its' shores, using it for trade and commerse.

The Son of Neptune
Just as Rome was founded on the shores of the Tiber River, the river has followed the Roman beliefs to Camp Jupiter, a training ground for Roman demigods. When Percy arrives at the Roman camp with the Gorgons close behind, he uses the waters of the river to create whirlpools and two giant hands made of water. The giant hands follow his commands and drag the two Gorgons under the waves, wripping them to dust and not allowing them to reform. The waters also seem to wash Percy's Achilles Curse away (as Juno had told him he would lose it), as after he is splashed with water, it felt like he had taken an acid bath and he felt vulnerable. After the danger had passed, he pulled Frank from the river.