A few years after immigrating from the Ivory Coast, Sekou Siby began working in the kitchen at Windows on the World—a restaurant on the 107th floor of the World Trade Center’s North Tower.

Sekou, 49, lost more than 70 colleagues on September 11, 2001, many of them immigrants as well.

He was originally scheduled to work on the morning of the attacks but switched shifts at the request of another employee—fellow kitchen worker Moises Rivas.

Sekou came to StoryCorps’ booth in Lower Manhattan to remember Moises as well as the many other coworkers he lost on that day.

Originally aired September 5, 2014, on NPR’s Morning Edition.