I have some pictures that are undersea scenes, but there is no suitable category for them (nautical is about 'boats' after all), nor for that matter is there any category for subterranean scenes. ALso, I'm not too sure about the Nature/Landscape category. What if one (as I have) makes landscapes that contain a good number of buildngs? That's certainly not a "nature" pic, and I don't think it should be forced into the "architecture" category when it's really a landscape [with] buildings. If nature and landscape were separate, there'd be no confusion, IMHO.