The 20th century was a tumultuous period in China. The Boxer Rebellion of 1900 sought to rid China of all foreign interests, and saw the massacre of countless missionaries and Christian converts. In 1921, the Communist Party was founded and periods of civil war ravaged the country, followed by war with Japan. Finally, in 1949, the country fell under Communist rule and officially became an atheist state. Due to religious intolerance and persecution, the Christian church was forced underground. Thousands of church buildings were destroyed or turned into civil facilities such as schools, warehouses, and factories.