Bosque de Chapultepec, named for the chapulines (grasshoppers) that populated it long ago, is the city’s largest park, a great green refuge from concrete, traffic, and dust. It’s also home to a castle, a lake, an amusement park, the Mexican president's official residence, and five world-renowned museums.
You can easily spend an hour at each Bosque de Chapultepec museum, with the exception of the Museo Nacional de Antropología, which is huge compared to its sister institutions. There you can have a quick go-through in two hours, but to appreciate the fine exhibits, anywhere from a half day to a full day is more appropriate. Tuesday through Friday are good days to visit the museums and stroll around the park. On Sunday and on Mexican holidays they're often packed with families, and if you get to the Museo Nacional de Antropología after 10 am on a Sunday, you can expect to spend considerable time waiting. If you have time to visit only one of Bosque de Chapultepec’s museums, make it the Museo Nacional de Antropología.