The major expansion in the municipality's demographics, like those of the other municipalities that circle Lisbon, occurred in the second half of the 20th century. Realizing this growth, and understanding that there was a need to control urban sprawl, in 1948 the "Plano de Urbanização da Costa do Sol" ('Sun Coast Urbanization Plan') was adopted to manage this activities in the northern margin of the Tagus. This remained active until 1994, when the first "Plano Director Municipal" ('Municipal Plan') was adopted.