Human beings are social groups that share behaviors, attitudes, and culture, which includes aspects like language and religion. Culture is the knowledge, attitudes, and behaviors shared over generations within a society or ethnic group. Culture changes over time through processes like innovation, diffusion, and acculturation. Major world religions developed and spread across continents through cultural diffusion and conversion efforts include Christianity, Islam, Hinduism, Buddhism, and traditional African and Asian belief systems. Creative cultural expressions vary between groups but can include music, dance, art, literature, and architecture.