Just as Arica is hugging the southern side of the Peru-Chilean border, so too is Tacna hugging its northern side. It's just an hour's ride, in a shared taxi, from Arica to Tacna; lots of Chileans hop over here for a few hours, to do some cheap shopping. Not very much to see here, and it has a bit of a bad reputation; but it's worth stopping here for an hour or two, before heading off to wherever else it is that you're going.
Crossed back into Peru today, from Arica in northern Chile; and I must say, it's good to be back! Almost feels like coming home again. The money looks familiar. The food looks familiar. And the people look familiar (and they have that familiar Peruvian friendliness). Got a shared taxi across the border this morning, from Arica to Tacna; and then it was a long evening's bus ride, from Tacna to Arequipa.