Hueyapan is a small that in the Mexican state of Morelos that has a church that forms a part of the UNESCO heritage site of the earliest missions established in the Americas.
This city in particular is on the border between the states of Puebla and Morelos, and has a spectacular viewing platform at the top of a hill (20 minutes on foot) which overlooks the Morelos side of everything.
There's a combi from Cuautla, going pass Ocuitucu and Tetela del Volcán.