The largest fortress in Europe is the Kalemegdan Fortress, located in Belgrade, Serbia. This historic fortification overlooks the confluence of the River Sava and Danube and has been pivotal in various military conflicts throughout history. Its construction began in the 2nd century and has undergone multiple reconstructions. The fortress features expansive walls, towers, and a park, making it a significant cultural and historical site. Kalemegdan serves as a symbol of Belgrade’s turbulent history and is a popular tourist destination, offering stunning views of the rivers and the surrounding landscapes.