On 9/11, chaos reigned across the City. All bridges, tunnels and trains were closed leaving millions stranded. Houston street was the barrier to downtown. Nobody could go past Houston street without ID to show that you lived there, or you were escorted by someone that lived there. By the evening of the 12th, several other checkpoints had been set up as you went further downtown. Canal street was the next checkpoint below Houston. And, closer to the World Trade Center, blockades completely closed off access to anyone. But for about 18 hours after the Towers fell; if you could get past Houston, you could go anywhere downtown.