Twenty-five years after the Tiananmen Square massacre, one expert says the crackdown actually helped church growth in China.
Loyola University of Maryland professor Carsten Vala said the brutal massacre caused many Chinese intellectuals and other elites to lose faith in communism and embrace Christianity.
The tragedy took place on June 4, 1989, when Chinese troops moved against student protesters in the square.
China's brutal crackdown on pro-democracy demonstrators left hundreds dead and plunged the country into chaos.
Since then, every June 4, the Chinese government tightens security. But on this 25th anniversary it's even tougher. Troops are on the streets of Beijing and police in greater numbers manning checkpoints around the square.
The government also has detained many critics of the communist regime.
Meanwhile, Vala said China's church has grown so large that the Communist Party fears its influence.
Despite the persecution of unregistered house churches, the number of believers continues to grow.
By some estimates, there are more than 100 million Christians in China.