Transport in Belgium is facilitated with well-developed road, air, rail and water networks. The rail network has 2,950 km (1,830 mi) of electrified tracks. There are 118,414 km (73,579 mi) of roads, among which there are 1,747 km (1,086 mi) of motorways, 13,892 km (8,632 mi) of main roads and 102,775 km (63,861 mi) of other paved roads. There is also a well-developed urban rail network in Brussels, Antwerp, Ghent and Charleroi. The ports of Antwerp and Bruges-Zeebrugge are two of the biggest seaports in Europe. Brussels Airport is Belgium's biggest airport.