Photographer Michael Wolf shot a series of photos called "100x100".

It explored the oldest public housing building in Hong Kong. He knocked on doors of each unit and persuaded its occupants to allow him to photograph them, and the interior of their flat.

Mr Wolf told The New York Times he was surprised at the response he received - 118 occupants were welcoming, and willing to be photographed.

"It shows that they have a lot of self-esteem about how they live," he said. (Photos: Michael Wolf)