On 14 September 2013, the Arctic Sunrise - a ship belonging to the environmental group Greenpeace - embarked on an Arctic expedition.
Its aim was to disrupt the first day of drilling on a newly built oil rig.
This would be the first to drill for Arctic oil - something that had only been made possible in recent years by melting ice in the region.
Frank Hewetson, a Greenpeace campaigner, was on board. He tells the story of the protest and arrest of 30 people by the Russian authorities.
A Falling Tree production for BBC World Service.
(Photo: Sign asking for Frank Hewetson's release. Credit: In Pictures Ltd/Corbis via Getty Images)