“if something containing iron oxide was heavily burnt, by natural or human actions, the iron particles in it can be permanently reoriented, like a compass needle, to align with the Earth’s magnetic field present at that point in time and space.’ The magnetometer detects differences in the orientations and intensities of these iron particles from the present-day magnetic field and uses them to produce an image of what lies below ground.Į Kerkenes Dag lends itself particularly well to magnetometry because it was all burnt at once in a savage fire. “The Earth’s magnetic field can vary from place to place, depending on what happened there in the past,” says Branting. It measures localised variations in the direction and intensity of this magnetic field. The first is magnetometry, which works on the principle that magnetic fields at the surface of the Earth are influenced by what is buried beneath. He started working with Dr Summers in 1995.ĭ The project used two main remote-sensing techniques. “Archaeology is a discipline that lends itself very well to remote sensing because it revolves around space,” says Scott Branting, an associated director of the project. The next stage was to use remote sensing, which would let them work out what lay below the intriguing outlines and ruined walls. By the end of the 1994 season, Dr Summers and his team had a jigsaw of aerial photographs of the whole site. Then one afternoon, he rented a hot-air balloon and floated over the site, taking yet more pictures. He walked over the entire site holding the balloon and taking photos. So he decided to use modern technology as well to map the entire site, both above and beneath the surface, to locate the most interesting areas and priorities to start digging.Ĭ In 1993, Dr Summers hired a special hand-held balloon with a remotecontrolled camera attached. Dr Summers quickly realised it would take far too long to excavate the site using traditional techniques alone. The 7 km perimeter walls run around a site covering 271 hectares. Excavating the ruins is a challenge because of the vast area they cover. The short-lived city came under Median control and only fifty years later was sacked, burned and its strong stone walls destroyed.ī British archeologist Dr Geoffrey Summers has spent ten years studying the site. Many respected archaeologists believe these are the remains of the fabled city of Pteria, the sixth-century BC stronghold of the Medes that the Greek historian Herodotus described in his famous work The Histories. Sprawled over the mountainside are the ruins of an enormous city, contained by crumbling defensive walls seven kilometers long. Sally Palmer uncovers more.Ī The low granite mountain, known as Kerkenes Dag, juts from the northern edge of the Cappadocian plain in Turkey. Thanks to modern remote-sensing techniques, a ruined city in Turkey is slowly revealing itself as one of the greatest and most mysterious cities of the ancient world.

The city lost to time