Children's chatter and laughter filled the National Art Museum of China last weekend. Many of the students from primary and secondary schools of Dongcheng District carried cameras and from time to time, snapped away at items of interest.

The youngsters would gather behind each other's cameras to examine the images on the LCD screen. Other students didn't need to look at their cameras to see their pictures. Their images were hanging on the walls of the country's supreme palace of art.

Ma Lanshi, 7, from the Shijia Primary School was among the youngest prize-winners. When he took photos, he often needed a tripod to support his light digital camera. "The Small Courtyard in Sunset" won first prize of the children section.

The second grader lives in a high-rise apartment, like many other city children, and had never been to hutong until he took part in the competition. His parents took him to the Mao'er Hutong and he soon pictured the scene that won competition.

The setting sun was casting its last rays through old trees upon the wall of a siheyuan courtyard, and two boys were playing next to a flight of antique stone stairs.

Life inside that siheyuan seemed attractive to the 7-year-old. "There were tall trees of long history in the courtyard, like the jujube, willow, elm, pear and peach trees. Kids could play together. I envied them," said Ma.

His photo is among a selection of 220 prize winners of the "Red Sandal Cup Retaining the Memories of Beijing" Grand Photo Competition, which are now on show in the museum.

The competition was jointly launched in September by the administrative government of Dongcheng District, the Beijing Daily News Group and the Beijing Bureau of Relics. It encouraged residents to take shots of the history and culture of the neighbourhood they live in.

The organizing committee received a flood of 11,500 photos in nearly two months. An appraisal jury consisting of 20 eminent experts in history, architecture and photography awarded 135 contributions of the adult category and 575 of the children category.

Jurors said the photos not only displayed the magnificence of the city's heritage, they also recorded the extensive renovations in these famous architectures, such as the Palace Museum.

They expose the changing life of old buildings and streets and new faces of siheyuan courtyard and hutong alleys.

During that process, photographers explored the relationship between inhabitants and the historical neighbourhood during this modern transformation.

The event has been popular with children and helped popularize the city they live in. Many schools organized students to visit relics, to exchange ideas with experts on the heritage protection and to learn dying handicrafts from folk artists. Educators saw it a chance for students to discover the beauty of the traditional culture.

Qin Xiaoyu, 17, from the Beijing No 1 Secondary School has practised photography for eight years under the guidance of teachers of the Beijing Teenagers and Children's Palace. Her montage photo of the Old Observatory won the first prize and stole the most attention on the exhibition. "I didn't choose the place intentionally. I was wondering in some hutong nearby, and my mum said the observatory might worth a shot. It was a sunny afternoon. But there were too many visitors. I waited for an hour in chilly winds till the closing time and people were all gone," she said.

The girl took six snapshots at different times. With the help of her father, a professional photographer, she edited them to form a full view, in which the Old Observatory appeared in silence and peace.

The background displays the glorious changes from a cloudy sky to the nightfall.

The exhibition occupies three halls on the fifth floor of the museum. It runs daily until December 25.

Dongcheng District covers an area of 25 square kilometres. It holds one third of Beijing's national-level historical heritages and one fourth of the city-level relic units, including such famous sites like the Drum Tower, the Clock Tower, the Yonghe Lamasery and the Zhihua Temple.