The Baha'i faith is a religion founded in Iran in the 19th century. It is based on the teachings of Bahá'u'lláh, who was born in Tehran in 1817 and declared himself to be a messenger of God. The Baha'i faith emphasizes the spiritual unity of all humankind and encourages its followers to work for the betterment of society. It has spread to many countries around the world and has millions of adherents.