Photo provided to China Daily

The Palace Museum released a report on May 15 on how the World Heritage Site is preserved in line with requirements that UNESCO imposed for better protection of the facility.

First built in 1420 and covering 1.06 square kilometers, the Palace Museum is the world's largest palace complex. It became a World Heritage Site in 1987, one of the first in China.

The Report on World Cultural Heritage Monitoring of the Palace Museum (2012) contains a detailed explanation of monitoring work in 10 areas — environmental quality, outdoor artifacts, architectural heritage, infrastructure facilities, basic platform construction, animals and plants, security, visitor trends, collections, and safeguard mechanisms.

Published in Chinese and English, the report is the country's first of its kind.

"It's how we fulfill the promise we've made to the whole world to better maintain the Palace Museum as a cultural heritage and inform the public on how we keep a close eye on this site," museum curator Shan Jixiang said.

Shan said the monitoring began in 2008, and has become part of the daily management.

"It's not our priority to use the relics to serve more tourists as a World Heritage Site. Our top mission is to keep them intact and leave them for future generations," he said.