The ancient War-Khasi people of India worked with the aerial roots of native banyan fig trees, adapting them to create footbridges over watercourses. Modern people of the Cherrapunjee region carry on this traditional building craft. Roots selected for bridge spans are supported and guided in darkness as they are being formed, by threading long, thin, supple banyan roots through tubes made from hollowed-out trunks of woody grasses.