Hotel Katari
For the view
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Regardless of where you are staying, you should go up to the rooftop bar on Hotel Katari to watch the sunset over the volcanos.
There is a fabulous view of the Plaza de Armas and cathedral framed by the Misti and Chachani volcanos.
I took the photo above at the end of November, which is supposedly the rainy season. However, I had sunny days the whole week I was in Arequipa.
Tables are limited, so plan to get there about an hour before sunset. There is a s/50 minimum per table, so be ready to order some food or cocktails while you watch the volcanos turn pink.