Slumscapes: How the world's five biggest slums are shaping their futures

Students attend the morning parade at a school in Kenya's Kibera slums in capital Nairobi, September 21, 2015. Kenya's president on Sunday urged teachers who have been on strike for about three weeks to return to work, saying their demand for a pay rise of up to 60 percent could not be met. REUTERS/Noor Khamis

LONDON (Thomson Reuters Foundation) - As the United Nations prepares a 20-year plan to cope with the challenges of booming urbanization, residents of the world's five biggest slums are battling to carve out a place in the cities of the future.

Home to more than 900 million people worldwide - or nearly one in every seven people - the U.N. says slums are emerging spontaneously as a "dominant and distinct type of settlement" in the 21st century.