Though there is no accepted consensus as to why so many of these new religious movements proliferated in South Korea, many trace their roots back decades to Japan's colonization of South Korea and the military dictatorship that ruled the country when it gained independence after World War II in 1945.

Many Koreans were pessimistic about the future during colonial rule, World War II and the Korean War. They lacked faith in their political leaders, and so looked to religious figures who promised them spiritual salvation, according to Tark.

Lee appears to have been one of them. The devout Christian was in his early twenties when he served in the South Korean Army's 7th Infantry Division during the Korean War from 1950 to 1953. After the hostilities ceased, Lee became one of more than a million followers of a charismatic Presbyterian elder named Park Tae-son.

The vision on the mountain

As Park addressed his fellow Christians at the top of Nam-San mountain, he claimed to see visions of fire and water descending from the heavens.

It was April 1955. Park was one of several religious leaders speaking at a massive revival rally held at what is now the site of Seoul's iconic YTN Tower.

Born in present-day North Korea in 1915, Park had attended Presbyterian church services from a young age, according to James Grayson, an emeritus professor of modern Korean studies at the University of Sheffield. But until that point, he had practiced an "orthodox line of Presbyterianism," said Grayson, a Methodist presbyter who lived in South Korea from 1971 to 1987 and studied the country's culture and religions.

"He had not been a part of any new religious movement before," Grayson said.

Park's vision led him to believe he had been spiritually cleansed and that his hands had been given "great power," Grayson wrote in his book "Korea -- A religious history." Park then stepped down from his lectern, and supposedly healed a man who had been crippled for 30 years by massaging him on the head.

It was a seminal moment for Park and new Christian religious movements in South Korea. The experience spurred him to establish his own movement, called the Olive Tree Church.

Though mystical forms of Christianity that combined biblical teachings and elements of Korean folk religion had existed before Park's visions on the mountain, none had ever had the same level of power and influence that Park's movement would come to have.

Olive Tree quickly became one of two new influential Christian religious movements in South Korea in the 1950s and 1960s.

The other was Moon Sun-myung's Holy Spirit Association for the Unification of World Christianity, better known as the Unification Church. Today it makes international headlines for its mass weddings, when thousands of young couples tie the knot at the same time, with some brides and grooms meeting their betrothed for the first time on their wedding day.

These sects and their unique practices were particularly appealing to South Koreans in the late 1950s and early 1960s. It was an era of upheaval in South Korean society, which was in the process of transforming from a poor, agrarian economy torn apart by a devastating civil war to one of the world's most modern and developed economies -- all in a single generation.

The economic leap, often called "the Miracle on the Han River," was spurred by the growth-minded military government of Park Chung-hee, which invested heavily in industrialization and infrastructure -- most of Korea's natural resources were located in the communist North.

From 1964 to 1995, per capita gross national income in Korea rose from $100 to $11,432, but the economic gains were not all shared equally. Those who did not reap the benefits of the Park government's moves "were disappointed by government policy after the Korean War," said David Kim, a professor at Australian National University and expert in Korean religion.

Many, Kim said, sought "internal peace" and these Christian sects filled the void.

A modern-day Zion

Park's Olive Tree religious group was a particularly attractive option for many Christians in South Korea. Its mission to establish a modern-day Zion appealed to many who felt left behind in the transition from an agrarian to an industrial society.

Park's faith healings, which he continued to conduct after his experience on the mountain, brought in many seeking spiritual, mental or physical rehabilitation -- including "ordinary people" who had little or no knowledge of Park's unique theology or teachings, said Kim.

People were drawn to the movement's wide-smiled leader with jet-black hair. Some even moved to a self-sufficient town built by Olive Tree, comprised of schools, factories and apartment complexes near Seoul.

The popularity, however, didn't last. Park eventually wore out his welcome with his parish when he claimed, according to Introvigne, that Jesus was an imposter and that he was the real Christ. His boast led to a string of mass defections in the mid-1960s. By the time he died in 1990, membership had plummeted.

Many of the white churches with crimson crosses across rural South Korea that once belonged to Olive Tree are now abandoned, "often used as village store-houses but no longer as places of worship," said Grayson.

One of those who left the Olive Tree religious movement was a Korean war veteran in his mid-thirties who had spent 10 years worshiping there.

His name was Lee Man-hee.

It would take a few more years, but on on March 14, 1984, Lee finally founded his own temple -- the Shincheonji Church of Jesus, the Temple of the Tabernacle of the Testimony, often referred to just as Shincheonji.

A similar script

Shincheonji's origin story is dramatic, but it's not particularly unique.

Experts say most Christian sects in South Korea followed a similar script. They formed as splinter groups from the Olive Tree movement or the Unification Church. Most still lean heavily on the vivid apocalyptic symbolism in the book of Revelations and are led by figures that claim a sort of divine right. Others, like Lee, hint at spiritual superiority via a connection to God or Jesus.

Grayson, the emeritus professor at the University of Sheffield, said that other Christians in South Korea view groups that question the authority of Christ as heretical. Fundamentalist protestants, a powerful political force in South Korea, are particularly distrustful of fringe Christian sects -- especially Shincheonji, which has been accused of poaching members of other churches.

While there may be hundreds of these fringe groups, experts say they are a product of South Korea's unique socioeconomic and political history, not necessarily representative of Christianity or religion as a whole in Korea.

Kim, the professor at Australia National University, believes Christian sects are viewed as suspicious by many South Koreans due to their "extreme evangelism."

"Ordinary Koreans would not know the existence of those minor Christian sects unless they have a personal connection through the relationship of family, friends or colleagues," he said.

"These groups constitute a rather small number of people," said Grayson. "But because of their nature (they) attract a lot of media attention."