Ostia is an ancient port city located at the mouth of the Tiber River in Italy. Founded in the 4th century BCE, it served as the primary harbor for Rome, facilitating trade and commerce. The city was known for its well-preserved ruins, including temples, baths, and a theater, which provide insight into Roman urban life. Over time, Ostia declined due to silting of the river and competition from other ports. Today, it is an important archaeological site, attracting visitors who wish to explore its historical significance and the remnants of Roman architecture and culture.