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Egypt, which was built in the 3rd century B.C. - one of the Seven Wonders of the Ancient World. It was an eight-sided tower on top of which was a cylinder that extended up to an open cupola where the fire that provided the light burned. On the roof of the cupola was a large statue of Poseidon (the Greek God of the Sea and Earthquakes) facing the sea, northward. It was said ships could detect the light from the tower at night or the smoke from the fire during the day up to 100 miles away. The lighthouse collapsed in the 14th century, probably as the result of an earthquake. The remains of Pharos are now at the bottom of the Mediterranean. Its name, however, has become the root of the word "lighthouse" in the French, Italian, Spanish, Portuguese and Romanian languages.2
Modern navigation aids
By the 21st century traditional aids to navigation have already gradually taken over. These include satellite navigation systems in order to cope with the needs of high speed and the huge volume of modern sea transportation. Even more recent inventions like the Radio Beacon and the Decca Navigator System are now almost obsolete.
The Global Positioning System (GPS), provided by satellites, is now the primary position fixing system for marine navigation. A public Differential GPS service is able to enhance the accuracy of GPS signals to within 10 metres up to 50 nautical miles around the coasts off the United Kingdom and Ireland. This system assists the safe passage of all classes of vessels from cargo ships, cruise liners and fishing vessels to small yachts. As a back-up system to the GPS, chains of Loran C on land are also adopted.3
Nineteenth century Hong Kong
In Hong Kong, things were quite different. There was not much sea traffic going to China before the first Opium War (1839-42) because of the Chinese policy of keeping its doors closed to foreign trade. Canton (Guangzhou), in the Pearl River Delta, was the city where limited foreign trade was permitted under stringent conditions. Macao under Portuguese administration served well as a buffer for foreign merchants waiting for the start of the trading season. Only after the Treaties of Nanking, Peking and Tientsin (1842-1860) was China forced to open up more and more ports for trade. Hong Kong's Victoria harbour became