Update: Read more in-depth coverage of this protest from Global Voices with many more photos here .
Several ten thousands have gathered at Seoul Plaza (as of 3 pm) to protest against the South Korean government's election manipulation scandal and the latest clampdowns on labor groups. The numbers are rapidly growing and the protest will continue throughout the day. Aiming 1 million Koreans to participate in ‘the December 28th General Strike’, a detailed schedule  [ko] of a series of protests held by different groups in major cities across the country has been widely shared in South Korean online venues in last few days.
— 방랑자 (@quegum) December 28, 2013 
The December 28 General Strike (and protest) against the fraudulent election is being held at the City Hall Plaza, now as of 3:22 pm.
서울광장 안 아닙니다. 광장 밖 도로에까지 꽉 찼습니다 pic.twitter.com/LnDUhrMUfy 
— 미디어몽구 (@mediamongu) December 28, 2013 
Actually it can't be said people are ‘in’ the Seoul Plaza. Even the nearby road s are packed with people.