Lake Plateliai (Samogitian dialect: Plateliu ežers) is the biggest lake in Samogitia and 9th biggest in Lithuania. It is the central attraction in the Žemaitija National Park. It covers about 12 km² and reaches up to 47 m in depth. It has seven islands, one of them housed a castle and now is called Castle Island. Archeologists found remains of two castles and think it might be the Queen Bona castle. The lake has both diving and yacht clubs.