In episodes 12 and 13 of “Do Do Sol Sol La La Sol,” Go Ra Ra (portrayed by Go Ara) was seen *spoiler warning* getting “married” to Cha Eun Seok (portrayed by Kim Joo Hun). In the same scene, Sunwoo Jun (portrayed by Lee Jae Wook) walks inside the church, grabs Ra Ra, and runs away from the altar.
The actual place where they filmed is at the Yakhyeon Cathedral in Jung-gu, Seoul. The church is said to be the first Catholic church and first Western-style church built in South Korea.