Iceland's renewable energy sources, hydropower and geothermal power, are the envy of fossil fuel-guzzling nations around the world. Nesjavellir, which produces municipal hot water and electricity from geothermal hot springs, was built in 1987 and attracts 20,000 visitors a year. Exhibits are informative, and the glassed-in observation platform affords a good view of the plant's gleaming pipery, but visitors expecting something out of a sci-fi movie may be disappointed. Reykjavík Excursions (tel. 562-1011; www.re.is) and Iceland Excursions (tel. 540-1313; www.icelandexcursions.is) include Nesjavellir in day-long bus tours, often combined with Þingvellir and the geothermal greenhouses of Hveragerði.