Larderello is a geologically active area in southern Tuscany, Italy, which is renowned for its geothermal productivity and was known from ancient times for its volcanic nature and exceptionally hot springs. The Romans used its sulphur springs for bathing. During the 18th and 19th century, they were exploited to extract boric acid. The region was the site of a pioneering experiment in geothermal energy production in 1904, when five light bulbs were lit by electricity produced through steam emerging from vents in the ground - the first ever practical demonstration of geothermal power. In 1911, the world's first geothermal power plant was built in the Valle del Diavolo ("Devil's Valley"), named for the boiling water that rises there. It was the world's only industrial producer of geothermal electricity until 1958, when New Zealand built a plant of its own. Larderello now produces 10% of the world's entire supply of geothermal electricity, amounting to 4.8 billion kwh per year and powering about a million Italian households.