Peseros (mini buses that used to charge one peso, hence the name) weave in and out of traffic alarmingly, cutting off anyone in their path in their determination to grab as many riders as possible.
Amid the astonishing bustle in this ancient metropolis, where well-heeled bottle-blondes with cigarettes, headscarved women and mustachioed men holding worry beads weave through winding streets choked with traffic, that is clear.