Estadio Ciudad de Lanús – Néstor Díaz Pérez, also known as "La Fortaleza" (The Fortress), is a multi-use stadium in Lanús, Argentina. It is currently used primarily for football matches and is the home ground of Club Atlético Lanús. The stadium holds 47,027 people and was built in 1929. In September 2010, the club started construction on a roof for the local stand, which has since been completed.