type of hill formation peculiar to that region, though the names are often adopted by geologists and used in a wider geographical context. These include: Brae – Scots, Ulster, and North of England term for a hillside or brow of a hill. Drumlin – an elongated whale-shaped hill formed by glacial action. Butte – an isolated hill with steep sides and a small flat top, formed by weathering. Kuppe – a rounded hill or low mountain, typical of Central Europe. Tor – a rock formation found on a hilltop; also used to refer to the hill, especially in South West England and the Peak District. Puy – used especially in the Auvergne, France, to describe a conical volcanic hill. Pingo – a mound of earth-covered ice found in the Arctic and Antarctica. Historical significance Many settlements were originally built on hills, either to avoid floods (particularly if they were near a large body of water), for defense (since they offer a good view of the surrounding land and require would-be attackers to fight uphill), or to avoid densely forested areas. For example, Ancient Rome was built on seven hills, helping to protect it from invaders. Some settlements, particularly in the Middle East, are located on artificial hills consisting of debris (particularly mudbricks) that has accumulated over many generations. Such a location is known as a "tell". In Northern Europe, many ancient monuments are sited in heaps. Some of these are defensive structures (such as the hillforts of the Iron Age), but others appear to have hardly any significance. In Britain, many churches at the tops of hills are thought to have been built on the sites of earlier pagan holy places. The Washington National Cathedral in Washington, D.C. has followed this tradition and was built on the highest hill in that city. Military significance Hills provide a major advantage to an army, giving them an elevated firing position and forcing an opposing army to charge uphill to attack a fort or other position. They may also conceal forces behind them, allowing a force to lie in wait on the crest of a hill, using that crest for cover, and firing on unsuspecting attackers as they broach the hilltop. As a result, conventional military strategies often demand possession of high ground. Hills have been the sites of many noted battles, such as the Battle of Alesia in 52 BC and the