The fortress on the outskirts of the city, next to the Danube, the fortress that existed from the Roman period, is the second largest fortress in Europe. As long as you climb the fortress, you know why they are building a fortress here. It is located at the cross of the river and is easy to defend. The Danube is not blue or romantic here, but the clouds in the sky are blossoming like cotton candy. Very good looking. Because I caught up with Sunday, plus the sun shining, the weather is very good, I feel that people from half a city come here to gather together. Everyone is in a circle, watching Serbian children dance. This famous fisherman's lighthouse is crowded like this, but it is no less than the Chinese. The hour and minute hands of the lighthouse are the opposite, and it is said that the fishermen can see the approximate time from a long distance.