From 1966 to 1976 Mao Zedong's cultural revolution banned all forms of religion so believers were arrested and imprisoned, churches were closed, and Christians were hardly persecuted.

All religious activity was forced underground, giving birth to the house-church movement. Further persecution seemed only to encourage further growth, despite horrendous cruelties inflicted on many thousands of church leaders.

Now in China there are about 80 million to 130 million Christians, with some 70 million in unregistered churches. Representing over 9% of the total population of 1.3 billion. That number will doubling or even tripling in the next twenty years.

This estimate, if correct, would constitute one of the most spectacular explosions in religious history and many experts say that an explosive growth in Christianity may be transforming the officially atheist regime.

Today the relationship between the Vatican and the Chinese government remains tense.

However nothing can actually stop the impressive rise of Christianity and even the president Hu Jintao is forced to assume positions of openness that were unthinkable a few years ago.