In 1920 French Equatorial Africa was established and Ubangi-Shari was administered from Brazzaville. During the 1920s and 1930s the French introduced a policy of mandatory cotton cultivation, a network of roads was built, attempts were made to combat sleeping sickness, and Protestant missions were established to spread Christianity. New forms of forced labor were also introduced and a large number of Ubangians were sent to work on the Congo-Ocean Railway. Through the period of construction until 1934 there was a continual heavy cost in human lives, with total deaths among all workers along the railway estimated in excess of 17,000 of the construction workers, from a combination of both industrial accidents and diseases including malaria. In 1928, a major insurrection, the Kongo-Wara rebellion or 'war of the hoe handle', broke out in Western Ubangi-Shari and continued for several years. The extent of this insurrection, which was perhaps the largest anti-colonial rebellion in Africa during the interwar years, was carefully hidden from the French public because it provided evidence of strong opposition to French colonial rule and forced labor.