Metropolis is a 1927 German expressionist film in the science fiction genre. The most expensive silent film ever made, it cost approximately 5 million Reichsmark. It is essentially dieselpunk, not steampunk. By the time this movie was most things were being run on electricity or diesel, not merely steam. Large machinery like ships, locomotives and some power plants were still powered by coal generated steam, but that was waning fast. Smaller vehicles like trucks and automobiles were already running on petroleum products like gasoline and diesel.