Photographer Colin Rich worked for months on this time lapse study of Los Angeles at night. He posts at Vimeo:
I sought out to capture the electric radiance of Los Angeles at night.It took me 6 months of on and off shooting to finish this project and I've learned a couple things along the way.
First off, LA might be the entertainment capital of the world, but it sure is difficult to shoot around downtown without having homeland security officers, police, or security take notice and harass you. Know your shooting rights!
Shooting time lapses is a labor of love and a study in patience.
To collect shots from behind the Hollywood sign, he writes, "every ten minutes a security car passed by and I had to jump over a fence off the main road and hide until they passed by. There are also infrared cameras all over the sign. I was sure I was going to get caught."