An explosion in Lagos, Nigeria rocked the city to its core. 23 people were killed, and a girls' boarding school totally destroyed. The Nigerian National Petroleum Corporation, the country's state-owned oil firm, said the blast in March occurred as a result of a truck that hit gas cylinders near one of its petroleum pipelines. But BBC Africa Eye's investigation indicates this explanation for the cause of the blast, that decimated over 100,000 square metres of the city, is wrong.