Sunday Adelaja never dreamed of becoming a megachurch leader when he left his Nigerian village at age 19. He was headed to the Soviet Union on a journalism scholarship. Only six months earlier, moved by an evangelistic crusade on TV, he had accepted Christ.

That was in 1986, when millions of Soviet peoples lived under the shadow of communism. The young Sunday had no idea that communism denied God's existence when he arrived in Minsk, Belarus. "I was so frustrated when I couldn't go to church—they said there's no church here," he says.

Sunday, 38, now leads what may be Europe's largest church, the 26,000-member Embassy of the Blessed King-dom of God for all Nations in Kiev, Ukraine. Started in 1994 among drug addicts and alcoholics, the Pentecostal church expanded rapidly.

Students, housewives, former Mafia members, wealthy businessmen, and powerful politicians pack a sports stadium for Sunday worship. Behind the main platform where Pastor Sunday preaches, rock music faintly pulsates—Ukraine's top athletes are pumping iron in the adjacent weight room. The beat doesn't distract the clapping, singing, and swaying men, women, and children focused on praising God. And they're not alone; thousands of other church members worship at 30 additional locations throughout Kiev. They're also changing the nation's social and political landscape.

Sunday began his journey in the Soviet Union as a "wilderness baby" whose faith matured quietly behind the Iron Curtain, akin to Moses's years of spiritual growth in the Egyptian desert. He quickly learned to survive at the state university by hiding his faith. He joined six other foreign students who secretly worshiped together.

After praying earnestly for several weeks, Sunday first glimpsed God's purpose in bringing him to the Soviet Union. He read in Isaiah 61, "The Spirit of the Lord is upon me to preach good news to the poor." God revealed to Sunday that crowds of Europeans would respond to his preaching.

For six years, Sunday struggled to trust God's plan. "I pretended I was asleep and prayed under my blanket. I had to have my morning devotions in the bathroom," he says.

When Sunday dared to hang a picture of Jesus in his dorm room, his roommate reported him. The local communist party leader and a professor banged on his door, demanding he take down the picture. They threatened to send him back to Africa. "The Lord spoke to me and said, 'Don't worry about removing the picture; just make sure they don't remove me from your heart,'" he says.

Sunday studied diligently and became a top student. "God used that time to train me, to help me master the language and understand European people," he says. He also started leading his student fellowship—more training ground for what lay ahead.

When Mikhail Gorbachev began opening the Soviet Union to the West, Sunday started his preaching career. On weekends, he and other local Christians visited churches and led evangelistic campaigns in Russia, Ukraine, the Baltics, and Belarus. But traveling without a visa was illegal for a foreigner, and in 1993 Sunday was caught and expelled from Belarus.

Just then, he was invited to work for Ukraine's first commercial TV station, which he quickly accepted. His fiancé;e, Bose, a Nigerian student whom he'd met in Russia, agreed to join him there.

After only a year in Kiev, Sunday felt God nudging him to begin a church, but he resisted. Each time he'd planted a church before, God had said, "Leave it; give it to the local people." Afraid of being separated from another church he'd birthed, Sunday asked God why he should start again.

"God said, 'I want you to raise up a country of strong men and women to reach other countries, especially where the Soviet Union has been known to send death, destruction, and tears. Instead, I want to use the Soviet people to bring healing, health, and the Good News,'" Sunday says.