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Summary: In May of 1990, law enforcement raided a warehouse in Douglas, AZ and a private home across the border in Agua Prieta, Mexico. Connecting the two buildings, they found a tunnel, more sophisticated than anything anyone had seen before. The tunnel in Douglas became a kind of prototype for many tunnels afterwards and a hallmark of the Sinaloa Cartel. <a href="https://99percentinvisible.org/?p=27918&post_type=episode" target="_blank">The Tunnel</a>