People read books at Duoyun Bookstore in Shanghai, east China, Aug. 12, 2019. Duoyun Bookstore in Shanghai officially opened to the public on Monday. Located at the 52nd floor of Shanghai Tower, Duoyun Bookstore offers readers and customers more than 60,000 books and a unique reading environment at a height of 239 meters. (Xinhua/Liu Ying)

People are seen at Duoyun Bookstore in Shanghai, east China, Aug. 12, 2019. Duoyun Bookstore in Shanghai officially opened to the public on Monday. Located at the 52nd floor of Shanghai Tower, Duoyun Bookstore offers readers and customers more than 60,000 books and a unique reading environment at a height of 239 meters. (Xinhua/Liu Ying)

People are seen at Duoyun Bookstore in Shanghai, east China, Aug. 12, 2019. Duoyun Bookstore in Shanghai officially opened to the public on Monday. Located at the 52nd floor of Shanghai Tower, Duoyun Bookstore offers readers and customers more than 60,000 books and a unique reading environment at a height of 239 meters. (Xinhua/Liu Ying)

A customer takes photos at Duoyun Bookstore in Shanghai, east China, Aug. 12, 2019. Duoyun Bookstore in Shanghai officially opened to the public on Monday. Located at the 52nd floor of Shanghai Tower, Duoyun Bookstore offers readers and customers more than 60,000 books and a unique reading environment at a height of 239 meters. (Xinhua/Liu Ying)

People read books at Duoyun Bookstore in Shanghai, east China, Aug. 12, 2019. Duoyun Bookstore in Shanghai officially opened to the public on Monday. Located at the 52nd floor of Shanghai Tower, Duoyun Bookstore offers readers and customers more than 60,000 books and a unique reading environment at a height of 239 meters. (Xinhua/Liu Ying)