Tread is a 2019 American documentary film directed by Paul Solet centering upon a 2004 attack upon the small mountain town of Granby, Colorado by welder Marvin Heemeyer, who destroyed a number of businesses and homes in that town with a secretly fortified bulldozer made up of steel, concrete, and guns after feuding with multiple residents. It premiered at the South by Southwest film festival in March 2019, and to limited theatres and on Netflix on February 28, 2020.