A 6.0-magnitude earthquake hit Changning County in southwest China's Sichuan Province on Monday night. After the earthquake struck, an earthquake warning was issued to many surrounding areas – including Chengdu – via TV and loudspeakers. This served to remind people to find shelter in time and protect their personal safety. What is an earthquake warning system and how exactly does it work? Join CGTN's Wei Lynn Tang to find more in Chengdu.