The philosophic thinkers of the Enlightenment predicted that religion would wither away, and that the world would become increasingly secular. This prediction has generally proven true in the developed world (Europe, Britain, Canada, Australia, Japan, etc., though not the United States) with participation in organized religion showing a dramatic decline. However, through much of the world, religion, far from fading away, has become central both to global politics and national identity, especially with the formerly atheistic Soviet Union undergoing a resurgence of Orthodox Christianity closely tied to Putin's extreme nationalism. Some of the major changes in world religion have been:
China: The communist revolution made atheism, as it were, a state religion. Although China in the past decades has experienced a renewed interest in Confucius, organized religion is discouraged and tightly regulated.
South Asia: Hindu nationalism remains a major force in India. The partition of India, with the Islamic areas eventually becoming Pakistan and Bangladesh and the Hindu area remaining in India, reveals deep religious fracture lines, with Muslim minorities in India, all non-Muslims in Pakistan, and Tamil Hindus in Buddhist Sri Lanka all often victims of religious discrimination.
Middle East: Divisions between Sunni and Shia Islam, and between radical jihadism and more moderate Islamic philosophies dominate middle eastern politics. The most significant currents of the past century are the rise of radicalism and Wahhabism, a very legalistic form of Islam.
Judaism: Perhaps the most important events of the past 150 years for Judaism were the Holocaust and the founding of Israel.
Roman Catholicism: The first and second Vatican Councils both marked philosophical shifts in Roman Catholic theology and practice. Other important trends are the rise of charismatic movements, the increasing importance of the global south, and the rise of liberation theology in South America.
Protestant Christianity: The past 150 years have seen a decline in the numbers of mainline, liberal denominations and the rise of evangelical and charismatic movements.
Future predictions: The assumption that religion would fade away seems mistake. According to the Pew Research Center, only 16% of the people in the world identify themselves as without religious affiliation. Religion will probably continue to be an important part of individual identity, and of global conflicts.
As for the future, Islam will be the fastest growing religion. It is expected that by 2050, there will be as many Muslims as there are Christians around the world. Now, Christianity still remains the most practiced by around 31% of the world's population. By 2050, more than 6 out of 10 people in the world will either be Muslim or Christian.