Unfortunately for arachnaphobes -- those with a fear of spiders -- spiders inhabit every continent except Antarctica. Scientists have already described about 38,000 living species, and they are constantly finding new ones. Spiders live in nearly every terrestrial habitat of the world, from the ocean intertidal zones, which are the areas between high and low tide zones along the coasts, to tall mountains. Spiders haven't found their way onto the snow-covered tops of many of the world's highest mountains, but scientists have recorded one species -- Himalayan jumping spiders (Euophrys omnisuperstes) -- living nearly 20,000 feet above sea level.