The blooming of the Atacama desert is a miracle of nature and the most impressive and beautiful phenomenon to take place in Chile. It occurs only every 4 or 5 years - from September to November - in years when rainfall is unusually high. This phenomenon is extremely unusual for a region that normally receives less than 12 mm (0.47 in) of rain a year, related to the El Niño climatic change. Over 200 species of flowers appear, all endemic to the Atacama desert.