The former market in Seville was going to be a shopping mall, but when they started digging, significant Roman ruins were found. The competition program involved protecting the ruins, reinstalling a market, and making an architectural attraction. It is hot in Seville and shade was a priority.
The original design was in metal, but the engineers determined that they could get more structural efficiency out of laminated veneer lumber. The contractor said "you want to build timber mushrooms in Seville? Are you nuts?