Four hundred years ago — on New Year’s Day in 1624 — drifting ice on the river Lek in the Netherlands smashed up a dike outside Utrecht. This was a pretty big problem in a country that is roughly one-third below sea level. Soon, the region was flooded, with even Amsterdam threatened by the water. The locals eventually managed to staunch the flood, but they still needed to do a full, durable rebuild — which would be extremely expensive. Fortunately, the Dutch were brilliant, sophisticated financi...