Longest Smuggling Tunnel Ever Discovered Between Tijuana And San Diego

Imagine building this thing. Where do you even start? Was there a plan or did the just say fuck it and start building? Where do you put the dirt that you dig up after 2,000 feet into the tunnel? Soooooo many questions. 

4,309 feet. That's under 1000 feet from a mile. 

I have anxiety just thinking about walking through that thing. Just looking at the photos!