Set atop a steep coastal hill 12km south of Corfu Town, the Achilleion Palace was built during the 1890s as the summer palace of Austria's empress Elisabeth, the niece of King Otto of Greece. The palace's two principal features are its intricately decorated central staircase, rising in geometrical flights, and its sweeping garden terraces, which command eye-popping views.
There’s surprisingly little to see inside, other than mementos of Elisabeth, who was assassinated in Genoa in 1898, and of the German kaiser Wilhelm II, who bought the palace in 1907 and added its namesake statue of Achilles Triumphant.
It's well worth getting an audio guide; the descriptions of various statues, paintings and background are excellent for context. Audio guides are free, but you'll need to hand over official government ID of some kind. You can use the guides for up to 50 minutes only.
Bus N-10 runs to the Achilleion from Corfu Town (€1.70, 20 minutes).