We took a boat ride in Recife last night. It was really just a short ride from one part of the city to the historic downtown area, which was surprisingly alive, considering that it was Christmas Day. I sampled a lot of the street food, as is my usual habit. One interesting thing I noticed was that whenever the boat passed under a bridge, the passengers clapped in unison. I supposed this was a local custom, perhaps having its origin as a way of warding off bad luck, or giving thanks for continued safety. No one I spoke to seemed to know the origin of the custom.