On 15 January, 21 people were killed in an attack on a luxury hotel and office complex in the Kenyan capital Nairobi.
The attack lasted 19 hours. But what exactly happened during that time?
Using 3D reconstructions, as well as new accounts from survivors, BBC Africa security correspondent Tomi Oladipo presents the most detailed picture yet of how the events of that day unfolded, from the start of the attack, to the swift and coordinated security response that saved hundreds of lives.
Video produced by George Wafula, Anthony Irungu, Ben Allen, Anthony Makokha, Hugo Williams, Millicent Wachira, Njoroge Muigai, Gloria Achieng, Ashley Lime and Muthoni Muchiri.