<P> The Great Chicago Fire was a conflagration that burned from Sunday, October 8, to early Tuesday, October 10, 1871 . The fire killed up to 300 people, destroyed roughly 3.3 square miles (9 km) of Chicago, Illinois, and left more than 100,000 residents homeless . </P> <P> The fire started at about 9: 00 p.m. on October 8, in or around a small barn belonging to the O'Leary family that bordered the alley behind 137 DeKoven Street . The shed next to the barn was the first building to be consumed by the fire, but city officials never determined the exact cause of the blaze . There has, however, been much speculation over the years . The most popular tale blames Mrs. O'Leary's cow, who allegedly knocked over a lantern; others state that a group of men were gambling inside the barn and knocked over a lantern . Still other speculation suggests that the blaze was related to other fires in the Midwest that day . </P> <P> The fire's spread was aided by the city's use of wood as the predominant building material in a style called balloon frame . More than two thirds of the structures in Chicago at the time of the fire were made entirely of wood, with most of the houses and buildings being topped with highly flammable tar or shingle roofs . All of the city's sidewalks and many roads were also made of wood . Compounding this problem, Chicago had received only 1 inch (2.5 cm) of rain from July 4 to October 9, causing severe drought conditions before the fire, while strong southwest winds helped to carry flying embers towards the heart of the city . </P>

Who caused the great chicago fire of 1871
find me the text answering this question