Since old times people - especially geologists - speculated about the interior of Earth. The Italian poet Dante Alighieri (1265-1321) imagined an allegoric center of the Earth: a frozen wasteland, not reached by the divine light, where Lucifer is entrapped in eternal ice.The French Sci-Fi author Jules Gabriel Verne (1828 - 1905) based " A Journey to the Center of the Earth " (1864) already on early science. In his novel Verne uses the hollow conduit of an Icelandic volcano to venture inside earth, an idea supported by the geologic models of volcanoes proposed at the time - a single or a series of magma chamber(s) with conduits connecting them to the surface. Geologists assumed that during an eruption the magma reservoir becomes empty and large voids and caverns were left behind.