Workers prepare to clean the walls of the Shanghai World Financial Center on Jan 4, the first working day this year. Their platform often rests 500 meters above the ground. YANG JIANZHENG/FOR CHINA DAILY Moving up and down a rope, stretching his arms wide to wipe as large an area as possible, the life of external wall cleaner Shang Qianjin hangs on two cables 14 millimeters in diameter whenever he works high in the air. The 43-year-old never thought he would enter the headquarters of China Central Television in Beijing's Chaoyang district, a building he had only seen on TV. Then, in 2018, he was employed to clean its external walls. Before starting work, he looked the building up and down. Although he was not supposed to look inside the building while cleaning it, he couldn't resist taking a peek. "It's beautiful. I wish my children or I had a chance to work inside," he said. Shang and his peers are known as "spidermen", and cleaning the external walls of skyscrapers is a booming profession. Many such buildings have sprung up since the reform and opening-up policy started more than 40 years ago. The CCTV headquarters is one of them, while the 632-meter Shanghai Tower in East China is the country's tallest building. A recent report by the Council on Tall Buildings and Urban Habitat in Chicago showed that by the end of last year there were 1,733 200-meter-plus buildings around the world, and China boasted 56 of the 106 completions globally. The country is also home to 18 of the 30 highest buildings projected for completion this year. In April, the Ministry of Housing and Urban-Rural Development and the National Development and Reform Commission of China issued a document on the management of urban and architectural features. The guideline imposed strict regulations on the planning and construction of skyscrapers. As one of the regulations was that no new building should exceed 500 meters, many architects had to reduce the heights of planned skyscrapers. High-altitude cleaners have to obtain a special operations certificate, which is overseen by the Ministry of Emergency Management. While they earn more than many other migrant workers, they also shoulder serious mental and physical challenges imposed by the work. As a result, few young people are willing to undertake the work.