What is the importance of the World Trade Center in the nonfiction book, The Undocumented Americans?

On September 11, 2001, the two buildings of the World Trade Center, also known as the Twin Towers, were toppled by planes that crashed into them. This disaster affected the whole country emotionally though New York City was additionally faced with tons of debris from the fallen buildings. Fallen ash covered, vehicles and easily seeped into the insides of buildings. Villavicencio discusses how immigrants were part of the force to help New York City—some as first responders though many as the second responders or cleanup crews. It was mostly immigrants who toiled at cleaning the ash and debris. One cleanup crew Member, Milton, described New York City as looking “like a Western, just like a desert” (34) and described that “the dust was hardest to clean because it blinded him and stuck to his wet clothing” (35). Villavicencio outlines that the subcontractors who hired the immigrants failed to give proper safety equipment to workers.