South Korea’s Yoido Full Gospel Church has the biggest congregation in the world. As of February 13, 2014, the Seoul-based Pentecostal Christian church had close to 1 million members. On any given Sunday, 200,000 faithful will attend 1 of 7 services and an additional 200,000 to 300,000 will watch on TV and in satellite churches.

Source: https://www.factretriever.com/south-korea-facts