Gaudi's fabulous La Sagrada Familia cathedral is well know for its innovative architecture. Gaudi was a fan of nature and tried to incorporate elements of it in his buildings.
While visiting La Sagrada Famlia, I notice a veritable zoo's worth of animal designs incorporated into the structure. Some, like a turtle bearing a pillar (above), or the exterior reptiles (below) are quite obvious.
A few mammals are represented, although I'm not sure what the dog-like creature is from around the west facing entrance (?coyote, ?wolf, ?rabid dog).
Most subtle and interesting were the insects and other small creatures incorporated into some of the metalwork around the doors. Look carefully at these images and see how many different types of critters you can see.