"The NSA’s Hidden Spy Hubs in Eight U.S. Cities"
https://theintercept.com/2018/06/25/att-internet-nsa-spy-hubs/

"These fortress-like AT&T buildings across the U.S. are central to a secret NSA program that has monitored billions of communications, documents and sources reveal."
"The NSA considers AT&T to be one of its most trusted partners and has lauded the company’s “extreme willingness to help.” It is a collaboration that dates back decades."
"According to the NSA’s documents, it values AT&T not only because it “has access to information that transits the nation,” but also because it maintains unique relationships with other phone and internet providers. The NSA exploits these relationships for surveillance purposes, commandeering AT&T’s massive infrastructure and using it as a platform to covertly tap into communications processed by other companies."