Close to the former entrance to the castle of Despot Stefan Lazarevic, near the remains of the drawbridge, a memorial was erected remembering the biggest and most glorious battle in the history of Belgrade, when the city acquired the famous epithet Bulwark of Christendom. It was at this place, on the bridge, during the night of July 21st 1456, that a decisive battle took place between the defenders of Belgrade and the Turks, led by the young Sultan Mehmed II, the conqueror of Constantinople.

It was the second siege in a row (the first took place in 1445) that ended with the city defended. The defenders of Belgrade were led by the then commander of the city, Hungarian nobleman Janos Hunyadi, better known in the Serbian tradition as Janko from Sibiu, and there were many crusaders among the fighters, gathered by the famous Franciscan missionary John of Capistrano. After the great victory, however, great joy did not follow, because, in addition to hunger and severe suffering from the attack, the city was hit by a plague epidemic that took the lives of many, including the two heroes Duke Janko Hunyadi and John of Capistrano. Unfortunately, Belgrade failed to resist the third Turkish attack, when after more than a month under siege, the city was conquered on 28th August 1521.