An adult movie theater is a euphemistic term for a movie theater dedicated to the exhibition of pornographic films. Adult movie theaters show pornographic films primarily for either a respectively heterosexual or homosexual audience. For the patrons, rules are generally less strict regarding partial- or full-nudity and public masturbation or sex, and such behavior may be condoned explicitly or simply tolerated by the management. Such behavior may or may not be legal, and if not, may or may not be overlooked by local law enforcement. Certain theaters may also include a stripshow or sex show between films, or other sex industry services. Before the VCR and, later, the Internet, a movie theatre or cinema house was often the only location where people could see hardcore erotic films. The spread of home videos and later of Internet pornography has led to a drastic reduction in the number of adult theatres. By region United States and Canada The earliest erotic theatres in the U.S. were in California, and showed 35-millimeter low-production-quality independently produced films. In 1960 there existed about twenty theatres in the U.S. that showed erotic movies exclusively. In the late 1960s and early 1970s, they spread to the rest of the country. The O'Farrell Theatre in San Francisco, one of America's oldest and best known adult-entertainment establishments, opened as an adult movie theatre in 1969. Small "storefront" theatres with only a dozen seats sprang up, and by 1970, 750 pornographic theatres existed in the U.S. In the 1970s, theatres shifted from showing 35-millimetre sexploitation films to more explicit 16-millimetre "beaver" films. In the 1980s, some theatre owners began forming chains to cut their costs, and, by 1989, the number of U.S erotic theatres had fallen below 250. Restrictions on adult theatres vary by region, and may be restricted by local and state regulations. Local governments commonly prohibit adult theatres from operating within a certain distance of residential areas, parks, churches and/or schools. Often, erotic theatres have been forced to move to the outskirts of cities in order to protect real estate prices in city centers. Renton, Washington was involved in a 1986 Supreme Court case regarding this issue. In its decision on Renton v. Playtime Theatres, Inc., the Court upheld Renton's statute that no adult theatre be located within 1,000 feet of a school, park, church, or residential zone; the Court rejected the theatre owners' argument that the statute violated