The English-language walking tour of the old town: the witches' market, the narrow alleys above Sagárnaga, Plaza San Francisco, and a singani at the end of it. It runs every day and it is the right first thing to do in a city at 3,600 metres, because you walk slowly and somebody explains why the rich live at the bottom of the valley.
They publish no address, no phone and no email. The only way to reach them is the WhatsApp number in their social row, which they at least make no secret of.