Colonia del Sacramento is the oldest city in Uruguay. It is located on the River de la Plata just across from Buenos Aires (there is boat service across this very, very wide and muddy river. Once a fort, then a peaceful fishing village, today it is a lovely place of old architecture, pretty beaches, and a Southern European feel. Visitors and residents will find a large yacht port, a beautiful basilica, and a small, walled section of the city with winding 17th-century cobblestone streets and old world architecture. A UNESCO World Heritage Site, this charming step into the past attracts Uruguayan and international visitors. There are several popular tourist sites include the oldest church in Uruguay.