This must-visit museum houses an invaluable collection of more than 200,000 artefacts representing the fascinating, tumultuous history of Yugoslavia. Photographs, artworks, historical documents, films, weapons, priceless treasure: it's all here. It can be a lot to take in; English-speaking guides are available if booked in advance via email, or you can join a free tour on weekends (11am in English, Serbian at noon). Marshal Tito's Mausoleum is also on the museum grounds; admission is included in the ticket price.
The museum's main building, known as the May 25 Museum, has undergone extensive renovations, and should have reopened the the time you read this. Take trolleybus 40 or 41 at the south end of Parliament on Kneza Miloša; ask the driver to let you out at Kuća Cveća.