The National Institute of Standards and Technology (NIST) and the technology magazine "Popular Mechanics" have investigated and rejected the claims made by 9/11 conspiracy theorists. The 9/11 Commission and most of the civil engineering community accept that the impacts of jet aircraft at high speeds in combination with subsequent fires, not controlled demolition, led to the collapse of the Twin Towers, but some conspiracy theory groups, including Architects & Engineers for 9/11 Truth, disagree with the arguments made by NIST and "Popular Mechanics".