It can boast one of the cleanest waters in the Lazio region and has been awarded the prestigious European Blue Flag for the pureness of the water for four consecutive years. The marine flora and fauna has also remained unspoiled; a carpet of Poseidonian algae, evidence of the best biological equilibrium, fringes the rocky promontories. The long, golden shores of fine sand are also a main attraction of Sperlonga. Two small lakes, called the eyes of Sperlonga, add charm to the landscape. The Lago Lungo is only just separated from the sea by a narrow line of dunes. The Lago San Puoto or San Potito has few fish but has a rich vegetation, home to many and rare lake birds. The lake is named after a small church and monastery built there at the end of the XII century and dedicated to San Puoto.