Christian activists in South Korea sent hundreds of thousands of gospel tracts over North Korea's closed border in November using helium-filled balloons. Equipped with a time-release mechanism, each balloon carried 10,000 leaflets that tell the story of a 1907 Christian revival in Pyongyang, and compare Kim Jong-Il to Nebuchadnezzar. The effort is part of a resurgence of balloon launches, used for decades by political and religious groups to send propaganda past the North's information blackout. Such launches worsened relations between North and South in 2008. In response, North Korea's government further restricted travel and communication between the two countries.