This one is literally for the birds. Lubetkin, a Georgia-born, Paris-trained, Russian architect, designed this pool for the penguins at the London Zoo in the 1930s. It was a prime example of pre-war Modern architecture, earning Lubetkin international praise and establishing his firm’s reputation as pioneers of the movement. The pool’s distinctive looping, interlocking walkways were meant to highlight the penguins’ waddling gait. Years later, it was discovered that the sloping paths were in fact giving the birds arthritis in their feet. The animals have since been shifted to another habitat, although Lubetkin’s pool remains—it is now classified as a water feature.