I'm not sure AC units work well in an open space. I used fans all over the place and they made a big difference, although I was sweating a lot. For that reason I had my photos taken before and my dress wasn't heavy, perfect for a tropical weather. We also had the cocktail hour in a salon (with AC) of the colonial house and people refresh from the heat drinking juices. It would be a waste having the wedding in a hotel salon (which you can do anywhere) if you are in Cartagena and not take advantage of the colonial architecture.
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