Sikhism is the fifth largest religion in the world. Originating in India in the 15th century, it is followed by over 20 million people worldwide. It was founded by Guru Nanak to bridge differences between Hindus and Muslims, to create an atmosphere of peace and goodwill. Sikhism is monotheistic and considers men and women equal before God with no priestly class. The Sikh scripture is the Guru Granth Sahib, a book that Sikhs consider a living Guru. Kirtan and Kundalini Yoga are popular Sikh practices that have risen in popularity in the West.