The Institute provides facilities for school and group visits and these have also included “Astronomical Weeks” (held on more than one of the islands in the group) and yearly open days. In 1985 the formal opening of the Institute engendered so much publicity that at the first open day at the Rocque de los Muchachos Observatory, 15 000 people attended. (The island’s total population is 80 000.) During 1986, a special event organized at a beach on Tenerife was attended by an estimated 70 000 people, thousands more being prevented by an enormous traffic jam. A month later, the inhabitants of La Palma switched off all private and street lights throughout the island for a period of 3 hours. Because of the interest and demand from local people and tourists, additional visitors’ centres are planned.