SOM, previously Skidmore, Owings & Merrill LLP, is a Chicago-based architectural, urban planning, and engineering firm. It was founded in 1936 by Louis Skidmore and Nathaniel Owings. In 1939, they were joined by engineer John O. Merrill. The firm opened its second office, in New York City, in 1937 and has since expanded, with offices in San Francisco, Los Angeles, Washington,... Wikipedia