Visitors view the famous scroll painting Along the River During the Qingming Festival in the Hall of Martial Valor in Beijing's Palace Museum on Sept 8, 2015.

The best-known scroll painting in Chinese art history－titled Along the River During the Qingming Festival－was completely unrolled for the first time since 2005.

The work by Zhang Zeduan (1085-1145), measuring 24.8 centimeters wide and 5.29 meters long, depicts a flourishing landscape in Bianjing, the capital of the Northern Song Dynasty (960-1127). Bianjing is today's Kaifeng in Henan province.

The scroll is only part of the special exhibition titled The Precious Collection of the Stone Moat, which includes 283 ancient paintings and calligraphy masterpieces once recorded in the Qing Dynasty emperors' catalog. The display is a main event celebrating the museum's 90th anniversary since opening to the public.

The Stone Moat, known in Chinese as Shiqu Baoji, is a royal inventory complied by 31 top-level scholars and art appraisers during the reign of Emperor Qianlong (1736-96).

It records about 11,000 paintings and works of calligraphy the emperor collected. After a seven-year investigation, 1,001 paintings and 228 works of calligraphy were found in today's museum collections.

People in long lines waited to enter the Hall of Martial Valor in Beijing's Palace Museum, also known as the Forbidden City, on Tuesday. But that was to be expected.

Other must-see exhibits:

Letter to Boyuan, by Wang Xun (349-400), the only surviving calligraphy from the Jin Dynasty (265-420) with an authentic signature by the writer.

Five Oxen, by Han Huang (723-787), the earliest surviving Chinese painting drawn on paper Spring Excursion, by Zhan Ziqian (545-618), one of the oldest surviving Chinese landscape paintings.