HONG KONG (CBS SF) — Video shot from a drone showed the massive scope of demonstrations in Hong Kong Monday.

Police fired tear gas into the crowd to contain pro-democracy protesters upset over China’s refusal to let anyone run for the Chief Executive of Hong Kong without approval from Beijing.

The video showed a sea of protesters as the drone rose over the crowd.

Protesters have been using social media to coordinate their demonstrations, including a San Francisco-Bay Area based app named Firechat.