Oaxaca's annual dance festival, called the Guelaguetza, doesn't officially start until towards the end of the month, but there seem to be all sort of events leading up to it, starting in early July. The first event that we came across was a parade one evening in the center of town.
These huge balloon-like things seem to be made of cloth, and people dance and spin them around at the same time. They look heavy, and I heard that these parades can go on for miles, so it's definitely a feat of endurance. In fact, everything about this style of dancing seems to involve carrying heavy things, mostly on your head, while you dance.
Here's a puppet dancer and a balloon dancer together.