1. Bratislava Castle
The white rectangular palace on the hill above the Danube has been burned, rebuilt, abandoned, and restored so many times that what you see today is mostly a 1950s-to-1960s reconstruction of a Renaissance-era building. The original fortification dates to the 9th century, when it was part of Great Moravia. Hungarian kings were crowned at St. Martin's Cathedral below, but they kept their crown jewels up here. In 1811, the castle burned to a shell and sat as a ruin for 140 years before the Slovak government rebuilt it.
Today the castle houses part of the Slovak National Museum's historical collection. Admission is 14 EUR, and the museum is open Tuesday through Sunday, 10:00 AM to 6:00 PM. The exhibits cover Slovak history from the Celtic and Roman periods through the Habsburg era, with a strong collection of period furniture and coins. The barrel-vaulted cellars are the oldest surviving spaces.
The castle grounds are free to explore and worth visiting even if you skip the museum. The formal gardens on the east side were replanted in baroque style, and the courtyard hosts occasional summer concerts. From the entrance gate, you are a 10-minute downhill walk to Main Square through narrow cobblestone lanes.