Cancun has already confirmed itself as a party town. The music from the 'nightclub' that was blaring down the road from my hostal when I arrived at 3PM is still blaring at 3AM as I try to sleep. Inverted commas are used around the word nightclub, as there seemed to be an inordinate number of girls in bikinis and PVC lycra outfits hanging around the front door when I walked past earlier. A shop across the street called Erectus would also suggest downtown Cancun might be fairly salubrious.
On a positive note, I have not heard any gunshots yet.
