Located in the heart of the Balkans, Belgrade is known as the key to the Balkans, where the Danube and Sava rivers meet. Belgrade has a variety of different styles of architecture, where you can pass or visit the National Museum of Serbia, the Belgrade National Theatre, the Nikola Pasic Square, the Kalemegdan Fortress, the Serbian Parliament Building, the St. Sava Temple. Joseph Broz Tito tomb. In the evening, walk into the Kalemegdan Castle and see the sunsets of the Danube and Sava Rivers. If you haven't gone to Europe, you can include it in your travel destination list.