This aquatic landscape on the western coast of Portugal extends along the coast for 45 kilometers from Ovar in the north to Mira in the south. At its widest point near the city of Aveiro, it reaches as far as 11 km inland at the Rio Vouga delta. The Ria di Aveiro is known for the rich biodiversity that has developed in this unique salt-marsh environment. The tides of the Atlantic replenishes the area with large quantities of salt water while the river deltas are a constant source of fresh water. Near the city of Aveiro, the Ria is even used for salt production. At high tide, the salt water is channeled onto special fields where sunlight causes the water to evaporate, leaving behind crystalline sea salt. The salt is then gathered into piles, which dot the landscape in the form of white cones.