Potential risks

Many people have asked Zhao about the locations in her photos, but she refuses to share the information. This, apparently, is a golden rule for urbex photographers. "Once you share the address, you never know who will visit the place and why they will go there," Zhao explains.

One example that illustrates the reticence to share a location's coordinates is a place in downtown Guangzhou, which is home to dozens of abandoned airplanes. It was a hidden place until someone shared the location on the internet. Many people, especially social media celebrities, went there to take pictures, leaving a sea of litter in their wake.

"The security guard is a man in his 70s, who has to patrol the place every day since more people have broken into it to take photos," Zhao says.

For urbex photographers, like Zhao, "take nothing but photos, leave nothing but footprints" is their motto.