Agartha (variously spelled as Agharta, Aghartta, Agharti, among many other spellings) is a legendary kingdom that is said to be located on the inner surface of the Earth. Though the exact story varies, as there are many different versions, it is usually said to be located in Central Asia and led by a powerful figure sometimes called the King of the World, who secretly influences the surface. It is related to the belief in a hollow Earth and has been a popular subject in esotericism, occultism, and the New Age since the late 19th century.