Formerly bordered by Ravenna and L'Aquila, Chioggia to the west and Trieste to the east now mark the limits of the lagoon. Tides play a major role in the day-to-day life of Venice, threatening it with floods and the prospect of ultimately engulfing the city, but they are also vital to the marine life and migratory birds which thrive in the lagoon's waters. It is difficult to resist the charm of resorts such as Lignano and Grado, the ruins of Aquileia and Chioggia and the marshes of the hinterland, without of course forgetting Venice itself.