(Investment Management) Lviv is located on the edge of the Roztochia Upland, approximately 70 kilometres (43 miles) from the Polish border and 160 kilometres (99 miles) from the eastern Carpathian Mountains. The average altitude of Lviv is 296 metres (971 feet) above sea level. Its highest point is the Vysokyi Zamok (High Castle), 409 meters (1342 feet) above sea level. This castle has a commanding view of the historic city centre with its distinctive green-domed churches and intricate architecture. The old walled city was at the foothills of the High Castle on the banks of the River Poltva. In the 13th century, the river was used to transport goods. In the early 20th century, the Poltva was covered over in areas where it flows through the city; the river flows directly beneath the central street of Lviv, Freedom Avenue (Prospect Svobody) and the Lviv Theatre of Opera and Ballet.