Ethmostigmus Rubripes is the largest centipede native to Australia, growing up to 14 cm long. Another species commonly referred to as “Giant Centipede,” Scolopendra Gigantea, is found in the American tropics and can reach 28 cm long. (http://www.britannica.com/eb/article-9022064/centipede#24668.hook)
Close-up of the “fangs” of a Hawaiian species of centipede.
Its large fangs behind its head are actually modified legs. It uses them to catch and immobilize prey with venom.
Most species of centipedes found in the United States are either too weak to pierce human skin, or if they can, their bite is typically no more severe than a wasp sting. (http://cufan.clemson.edu/hgic/factsheets/hgic2550.htm)
Background image courtesy of http://davids-pics.blogspot.com/2007_04_01_archive.html