Casa Serpiente, or "Snake House," is named for the way its undulant form twists through a tree-studded garden in Lima, Peru. It almost never rains in the Peruvian capital—the second-largest desert city in the world, after Cairo, Egypt—so trees are precious here. But this grove had even greater significance for its owners, a husband and wife named Irzio and Lisette. Irzio fondly remembers playing here as a child, when it was his parents’ backyard. So when the couple decided to build their new home in this green oasis, the husband recalls, "There was never any question: The trees had to stay."