The Sikhs are adherents to Sikhism the fifth largest organized religion in the world, with around 25 million adherents. Sikh History is around 500 years and in that time the Sikhs have developed unique expressions of art and culture which are influenced by their faith and synthesize traditions from many other cultures depending on the locality of the adherents of the religion. Sikhism is the only religion that originated in the Punjab region with all other religions coming from outside Punjab (with the possible exception of Punjabi Hinduism since the oldest Hindu scripture – the Rig Veda – was composed in the Punjab region. Some other religions, like Jainism, may also claim to have originated in Punjab since Jain symbolism has been found among artifacts of the Indus Valley Civilization). All the Sikh gurus, many saints and many of the martyrs in Sikh history were from Punjab and from the Punjabi people (as well as other parts of the Indian Subcontinent). Punjabi culture and Sikhism are mistakenly considered inseparably intertwined. "Sikh" properly refers to adherents of Sikhism as a religion, strictly not an ethnic group. However, because Sikhism has seldom sought converts, most Sikhs share strong ethno-religious ties as therefore it's a common stereotype that all Sikhs share the same ethnicity. Many countries, such as the U.K., therefore misconcievingly recognize Sikh as a designated ethnicity on their censuses. The American non-profit organization United Sikhs has fought to have Sikh included on the U.S. census as well, arguing that Sikhs "self-identify as an 'ethnic minority'" and believe "that they are more than just a religion". There is a common misconception that all Sikhs belong to the Punjab region. The religion's birthplace of Punjab itself has been called "India’s melting pot", and many other parts of Northern India due to the heavy influence of invading cultures, such as Mughal and Persian, that mirrors the confluence of rivers from which the region gets its name(from Persian,"panj" پنج meaning "five" and "-āb" آب meaning water thus meaning land of the five waters).