34629 The United Nations estimates only 10% of the trash in Africa actually makes it to a dump. The rest is left to rot in communities, or it’s burned in smelly bonfires. In Lagos, Nigeria -- the largest city in sub-Saharan Africa -- authorities hold a monthly clean up day. By law, the last Saturday of every month is Sanitation Day in Lagos. The entire city comes to a stop as people spend hours sweeping the streets and cleaning up trash. Sarah Simpson reports.