Culminating days of fierce resistance against plans to drill for Arctic oil, activists in Seattle on Monday are risking arrest as they attempt to shut down operations at Shell Oil’s drilling rig.

In the wee hours Monday morning, hundreds of people stopped traffic on the Spokane Street Bridge before marching to the Port of Seattle where protesters blocked the entrances to Terminal 5, which houses the oil giant’s floating rig, the Polar Pioneer.

A coalition of local environmental organizations, known as the sHellNo! Action Council, have for days been holding nonviolent training seminars in order to prepare activists for what is being described as “the largest act of environmental civil disobedience Seattle has seen in recent years.” Among those risking arrest is Seattle city councilmember Kshama Sawant.

“Today we’re not just shutting down Shell, we’re challenging corporate capitalism, imperialism and colonialism with a vision of people power and true mass democracy,” said Ahmed Gaya, an organizer with Rising Tide Seattle, one of the groups participating in the council.

KPFA is live-streaming the direct action here and Seattle alt-weekly The Stranger also has live coverage throughout the day. Other updates are being shared online under the hashtags #YouShellNotPass and #sHellNO.