The separation of Tres Cantos Curiosity · Tres Cantos, Área Metropolitana, Madrid Conceived as an urgent town-planning scheme under the decree of 1970 and inspired by the British new towns, the town took in its first residents in 1982 and did not separate from Colmenar Viejo until 21 March 1991. Photo: bass_at_home (CC BY-SA 3.0) What to see and do in Tres Cantos