Chapultepec Park and Xochimilco
Chapultepec Park is the Central Park of Mexico City. It is a world-class park, with an amusement park (which we thorougly enjoyed), playing fields, a zoo, several museums, the national music hall, and historical points of interest including Chapultepec Castle, the ruler's castle in colonial days.
The "floating gardens" of Xochimilco are really island gardens separated by canals. The way you see them is to take a boat -- much like doing a tour of the buildings in Venice by barge.
Back in Parkchester, one wall of our apartment had a series of photos Dad took on a previous trip to Mexico before he was married. Each picture was captioned, so I recognized the name "Xochimilco" from having passed it many times a day while growing up. Now I knew what it meant, what it was. That would happen several times over the next two weeks, as we retraced some of Dad's steps.