Explore Charles Bridge and Prague Castle, famous Prague attractions on the Vltava River. Prague Castle is the most popular sight in Prague. It towers on an elevated hill on the left bank of the Vltava River – with its distinctive panorama it, along with Saint Vitu's Cathedral, dominate the Prague skyline. The Charles Bridge is 516 meters long and nearly 10 meters wide, resting on 16 arches. Charles Bridge is a busy place with painters, kiosks' owners and other traders alongside numerous tourists crossing the bridge.