The Intercept revealed eight AT&T-owned locations that serve as NSA spying hubs. The sites are located in California, Washington D.C., New York, Texas, Illinois, Georgia, and California. NSA surveillance programs seem to have taken place at these eight facilities. The Intercept article cites a top-secret NSA memo that has not been disclosed before; the memo explained that the agency was collecting peoples messages en masse if a single one were found to contain a selector like an email address or phone number featured on a target list.”]
Source: https://www.csoonline.com/article/3284073/8-att-buildings-that-are-central-to-nsa-spying.html