The boulders on the beaches along Avenida Montevideu are some of the most ancient in the world (292 ± 5 Ma (Rb/Sr, biot.)), forming the Metamorphic Complex of the mouth of the River Douro, classified as Municipal Natural Heritage. The redevelopment of the seafront has served to integrate this landscape into the daily circuits of both locals and visitors, giving it a sense of order and tempering its rather hostile appearance.