However, farming on chinampas has its own challenges. After the Spanish conquest of Mexico in 1521 and subsequent rapid urbanisation, chinampas fell out of favour. In the second half of the 20th Century, Mexico City rapidly expanded outwards and engulfed a substantial percentage of Xochimilco"s floating farms. The final blow came in the form of the Xochimilco Ecological Plan in 1987, which brought about the expropriation of 2,577 acres of communal agricultural lands and permitted an increase in urban usage such as the construction of buildings, bridges and football pitches.