Steampunk is a sub-genre of science fiction, alternate history, and speculative fiction. Specifically, it involves an era or world where steam power is still widely used—usually the 19th century and often Victorian era Britain—that incorporates prominent elements of either science fiction or fantasy. Works of steampunk often feature anachronistic technology or futuristic innovations as Victorians may have envisioned them; in other words, based on a Victorian perspective on fashion, culture, architectural style, art, etc. This technology may include such fictional machines as those found in the works of H. G. Wells and Jules Verne or real technologies like the computer but developed earlier in an alternate history. Other examples of steampunk contain alternative history-style presentations of "the path not taken" for such technology as lighter-than-air airships, analog computers, or such digital mechanical computers as Charles Babbage and Ada Lovelace's Analytical engine.