The Dragon's Den was a safety hideout used by the Chinese army.
The Dragon's Den was a safehouse in case of a emergency in China. It had military sections that were restricted to the public, and four barracks called Claw, Fire, Fang, and Wings, which were used by Chinese citizens during the First Formic War.
The Dragon's Den was used during the First Formic War to protect Chinese citizens from the Formics. The Dragon's Den civilian areas were packed full. The Dragon's Den was also planned to be used by the Chinese People's Liberation Army in order to research the defoliant spray the Formics were using.