Foulness Island level, which was above the danger level for this part of the Essex coast. This level in itself was not a danger to the island, as the sea walls had been raised and strengthened between 1951 and 1952 by the War Office, and were above mean sea level. However, the high water was accompanied by strong winds, creating large waves, which broke over the top of the defences, washing away the earth banks on the inland side of the walls. Two sections of the wall breached, from Rugwood Head to Asplin's Head on the eastern side of the island, and
Island of the Jewel broadly. The four chorographic maps of the 1037 manuscript of al-Khwārizmī—including that of the Island of the Jewel—are the oldest surviving maps from the Islamic world. Al-Khwārizmī gave the Island of the Jewel as the easternmost point of the inhabited world. His gazetteer is divided by categories but altogether he provides coordinates for its coast, three cities, its surrounding chain of mountains, and two summits on the interior. It lies in the Sea of Darkness near the equator, east of his equivalent of Ptolemy's Golden Peninsula (Malaysia) and east of the still larger phantom peninsula—now usually known as the Dragon's