China's 21-year-old Spider-Man says what he cares about most is the freedom of standing in the air. Wang Jing / China Daily

With his bare hands and no safety equipment, Zhang Xixin scales the outside of a five-floor building within two minutes.

Having reached the top, the thin youth looks down through his black-framed glasses and poses on the edge of the roof like Spider-Man.

"Climbing is one of my hobbies. I take it as a game," said the 21-year-old firmly.

"Tall buildings are like final monsters in a computer game and I'm the brave player," he said.

"As I stand at the foot of those high buildings, I feel I've entered game mode."

He studies ways to climb skyscrapers as he passes by, and can't help trying to climb them.

"Buildings with many stories grab my attention and I have an impulse to scramble up them," he said.

"I enjoy the feeling of rising high into the sky."

Zhang, from Linyi city of Shandong province, used to climb up to the roof of his house when he was a little boy, which always annoyed his parents.

He could go up to the top of houses more quickly than children of his age.

A scar, a reminder of falling from a roof, can be clearly seen below his left eyebrow.

He didn't become serious about scaling buildings without equipment until last September when he posted a photo online showing him atop a residential building.

But instead of people marveling at him, as he had expected, most netizens doubted the authenticity of the picture and thought he was trying to grab fame.

"I was puzzled by or even angry with those responses for a couple of days, because I really like climbing without equipment and just wanted to make friends, who are also interested in it," he said.

To prove his ability to climb, he has since challenged tall buildings, like the French climber Alain Robert, who is also known by the nickname Spider-Man.

"I admired the French man's persistence in scaling buildings," Zhang said.

"He plans before climbing, but not me. Mine are at will."