Palaio Frourio is an old citadel, old Venetian fortress built on top of an islet, being surrounded with fortifications. Parts of its perimeter (eastern part) suffer erosion, being lost in the sea.
The Archeological Museum of Corfu Town impresses, the many archeological exhibits aside, by its famous Gorgon Medusa statue and other works of art in Greece
As far as northwestern beaches go, the Sidari Beach, part of the homonymous resort, is said to be the most impressive of all, which is why it is so highly frequented.
Trips from Corfu to Paxi (Paxos). Visit Paxos main town - Gaios. The island only one hotel but plenty of rooms in villas and apartments for rent.