After 9/11, the government began encouraging local police, private security and everyday Americans to report so-called "suspicious activity" that may indicate a security threat. Taking photos of landmarks, walking "nervously" and writing in a notebook are all activities that have led to people being stopped and questioned. Could you be next? Directed and produced by Carrie Ching Reporting and research by G.W. Schulz, Andrew Becker, Tia Ghose, Daniel Zwerdling, Margot Williams Illustration and animation by Arthur Jones Music by Lukasz Stasinski and Erik Haddad Learn more at http://americaswarwithin.org Have you been stopped for engaging in "suspicious" activity? The Center for Investigative Reporting wants to hear from you: http://publicinsightnetwork.org/form/center-for-investigative-reporting/1efa0f1f3447/homeland-security