These surfers are often referred to as "surf punks" or "surf nazis." The local surfer gangs in Southern California (Malibu Locals Only and Lunada Bay Boys) and those on Hawaii island (Da Hui) have been known to threaten visitors with physical violence for invading their territory. In Southern California, local surfers are especially hostile to the surfers from the San Fernando Valley whom they dub "vallies" or "valley kooks". The expression "Surf Nazi" arose in the 1960s to describe territorial, aggressive, and obsessive surfers, often involved in surf gangs or surf clubs. The term "Surf Nazi" was originally used simply to denote the strict territorialism, violence and hostility to outsiders and the absolute obsession with surfing that was characteristic in the so-called "surf nazis." However, some surfers reclaimed and accepted the term, and a few actually embraced Nazism or Nazi symbolism. Some surf clubs in the 1960s, particularly at Windansea in La Jolla, embraced the term by using the swastika symbol on their boards and identified with Nazism as a counterculture (though this may have just been an effort to keep out or scare non-locals and may have been a tongue-in-cheek embrace of the "surf nazi" label as a form of rebellion). The "locals only" attitude and protectionism of the Santa Monica surf spots in the early 1970s was depicted in the movie "Lords of Dogtown", which was based on the documentary "Dogtown and Z-Boys".