Illustration by Athanasius Kircher from his 1664 book Mundus Subterraneus. It depicts a section of the earth with a great fire at its center, which communicates with many smaller bodies of fire; also many caverns within the earth filled with water; volcanoes, fumaroles and hot springs are also included. Kircher (1601-1680) was a German Jesuit scholar, a scientific star in his day, he published around 40 works ranging in subject matter from oriental studies to geology to medicine.