Venice has been known as "La Dominante", "La Serenissima", "Queen of the Adriatic", "City of Water", "City of Masks", "City of Bridges", "The Floating City", and "City of Canals". The lagoon and the historic parts of the city within the lagoon were inscribed as a UNESCO World Heritage Site in 1987, covering an area of 70,176.4 hectares (173,410 acres).[14] In view of the fact that Venice and its lagoon are under constant threat in terms of their ecology and the safeguarding of the cultural heritage, Venice's UNESCO listing has been under constant examination by UNESCO