Ross Ching's Empty America series reveals what cities would look like if all the humans disappeared. After launching with a time-lapse portrait of San Francisco, the series goes on to tour Seattle. The footage is desaturated almost to grayscale for a particularly bleak, post-apocalyptic look. 

Ching, who directs the series for Thrash Lab, explains how he removes people and moving cars in this making-of video. Below, he describes the work that goes into choosing locations. In any given city, he has to cover 30 to 40 locations in just a couple days, he says. To save time, he scouts ahead with Google Street View to plan shots in advance.

For more work by Ross Ching, visit http://rossching.com/.