People have been carrying heavy loads on their heads since ancient times. It's very common in developing countries when there is no car nor mule to assist with the shopping. Simply roll-up a towel, shape it into a circle and place it on your head. You're then ready to carry up to fifty-times your own body weight. Or am I thinking of ants?
In East Africa, the women of the Luo tribe carry up to 70% of their body weight on top of their heads. They must have really great posture, though I'd hate to see the state of the discs in their necks.
But the mercado ("market") in Antigua, Guatemala must have had some issues with these basket cases. Perhaps people were knocking into things or spilling their loads all over the place. Or perhaps there was a problem with shoplifting - it would be easy to quickly toss stuff into the basket without anyone knowing.
Nevertheless, in the central market of Antigua, you're not allowed to enter with a load on your head (below).
[Below] In the centre of the forbidden: Carrying burdens on heads is not permitted.
