The Campo del Cielo (field of heaven) meteorite-strewn crater field, one of the largest in the world, lies to the west of Chaco province on the border with Santiago del Estero. It is believed to have been created when an 800-ton asteroid broke up into pieces on entry to the earth’s upper atmosphere some 4,000 to 6,000 years ago. And the resultant shower of meteorites plummeted to earth where on impact they formed more than 20 large craters. In one such crater the largest meteorite dubbed El Chaco was discovered and subsequently dug up by the Fuerza Aérea Argentina in the 1980s and placed alongside the crater. The meteorite weighed in at a colossal 37.4 tons.

The existence of the meteorite field was first recorded in 1576 by the Spaniard Hernán Mexía de Miraval. He, with the help of the indigenous Indians, was hoping to gold or silver, not iron, their main component. One of his specimens, the Meson de Fierro inspired several subsequent expeditions who travelled to the Chaco to determine its nature. In 1776 Captain Francisco de Serra took samples of the Meson and concluded that it comprised a special type of iron. Some years later in 1783 the governor of Tucuman sent Miguel Rubin de Celis and a vast team of men to carry out a series of explosions beneath the Meson, only to discover the earth below not a mountain of iron. Its former location remains unknown.

In 1825 a large part of another meteorite - over 600 kilos - Runa Pocito, discovered in 1803, was donated to the British Museum by the British Consul Woodbine Parish and was the first meteorite from Campo del Cielo to go on public display.

In 1969, a team of scientists headed by the American Dr William Cassidy, discovered El Chaco, the second largest meteorite in the world after Namibia’s 60-ton Hoba. Robert Haag or meteorman as he was later nicknamed tried to remove El Chaco in 1990 in order to ship it back home to America. However, his plan was foiled and provincial laws were quickly passed to stop their removal, while the Parque Provincial Pinguen N’onaya was created to protect them.

In 2005, funded by the National Aeronautics and Space Administration (NASA), Dr Cassidy returned to the Campo del Cielo where he proceeded to excavate other meteorites such as nearly 15-ton La Sorpresa and the close-to-eight-ton El Wichi. The Fiesta Nacional del Meteorito has been staged annually ever since. The Campo del Cielo is some 15 km south of Gancedo, the nearest small village.