Nst tonight, for the first time, American cameras take you inside a secretive religion. Decades ago, we heard about a wedding of 2,000 couples in new York City. Tonight, juju Chang is here with rare... See More
Nst tonight, for the first time, American cameras take you inside a secretive religion. Decades ago, we heard about a wedding of 2,000 couples in new York City. Tonight, juju Chang is here with rare access and she found that this happened recently again. Reporter: Imagine a wedding with 2,000 couples, some who barely know each other. That's what's happening at this stadium outside Seoul, south Korea. All are members of the unification church, founded by the late reverend sun Myung moon, a self proclaimed messiah. Two years after his death, we were surprised to find his followers taking part in the phenomenon that earned the church so much attention in its heyday. The movement holds these weddings once a year. It says it has 3 million members worldwide, but critics say the number is closer to 100,000. Many of these brides and grooms are the children of the original followers, taking their turn at the altar after being matched through a church database. Among them, Glenn and his fiancee judilee. She is an aspiring artist, flew from Canada to meet Glenn, a frontman for an indie band. They had never before laid eyes on each other. How do you explain that concept to the outside world, that I let my parents help me pick my mate? Sometimes I feel a little bit self-conscious. But I feel it's not just marrying two people, it's like marrying two families. Reporter: Both Glenn and judilee's parents were matched by reverend moon, his core belief, that multicultural unions would eliminate racial strife and usher in world peace. And in Korea, we caught up with them moments before the wedding. How do you feel? Good. Kind of like, surreal. Reporter: As couples line up, the most important guest is arriving. True mother, reverend moon's widow. She leads the elaborate ceremony. The exchange of rings for all 2,000 couples. Definitely felt like our moment. Even though we're in a sea of brides and grooms, I felt like it was our moment. Reporter: As they make their way out as married couples, most will sleep apart for 40 more nights as a final act ofth. But, as true mother would say, they have an eternity to get to know each other. Juju Chang, ABC news, south Korea. And you can see the full report on "Nightline prime"
This transcript has been automatically generated and may not be 100% accurate.