Tsilivi is definitely one of the places you should visit during your stay on Zakynthos. About a 5-minute car ride from the capital (6km), it is mostly known for the long beach where all facilities are available.
Apart from swimming in the shallow crystal-clear waters, the Milanio Maritime Museum is worth a visit, with a respectable collection of marine treasures. Visit the museum's official site www.milaniomaritimemuseum.gr. for more information.