■ View the South Sea from 158m high. Geoje-si, Gyeongsangnam-do, preparation site for the opening of Geoga Bridge, which has already become a landmark of South Korea. The main tower, which boasts the highest height in Korea at 158m, is in the final safety test, and although it is a dizzying height where you can see Geoje Island and Busan in the distance, it is very familiar to the workers who commute here every day. On the bridge, a test run is in full swing, taking 50 minutes by car along the road that divides the sea. The total length is 8.2km, and in particular, the submarine tunnel that penetrates Gadeokdo, Jungjukdo, and Daejukdo is 3.7km long, making it the longest submarine tunnel in the world. The 180m-long, 45,000-ton ship is connected at a depth of 48m, and in a few days, the ship journey from Busan to Geoje, which used to take 2.5 hours, will now take 40 minutes. Recently, the Geoga Bridge, a gigantic structure boasting its grandeur, has attracted the attention of not only local residents but also the world, because its very existence has historical significance. ■ When everyone says it can't be done, that's the opportunity for a challenge! The construction team that first planned the construction and visited the Netherlands to seek advice, however, waved their hands, saying that they could not build an immersed tunnel under the sea. The problem was the unimaginably poor environmental conditions. There have been immersed tunnels in over 140 places around the world, including Europe and Japan, but they were all built in inland seas or bays. Not only had they never been built in the open sea with strong waves, winds, and currents, but they also argued that it would be very difficult to connect the hulls if built in deep waters due to the strong buoyancy. During the construction process, these concerns became reality. It was fine when connecting the hulls in shallow waters, but a problem arose when connecting the hull number 5 at a depth of 34m. The special rubber connecting the hulls was irregularly crumpled and not properly connected, but after much trial and error, the technicians solved the difficult problem by adjusting the buoyancy by injecting air into the hulls. Using Korea's technology, they solved problems that the world's best technicians had avoided. The perseverance that pushed forward when everyone else said it couldn't be done is the beginning of the Geoga Bridge. ■ Moses' Miracle? The Miracle of the Geoga Bridge The world's first offshore immersed tunnel connection site. It takes about 6 hours to trim the 80-meter-long hull. The strict condition that the wave height must not exceed 0.4 meters for 5 consecutive days must be met in order to safely sink the gigantic 47,000-ton hull. The tens-of-thousand-ton hull must be placed in the exact seabed location and constructed within a margin of error of 1-2 cm to maintain safety, and it is a precise task that can be said to be 'shooting a gun with your eyes closed.' The problem grew as the work progressed. Although the equipment was imported from overseas, it could not be applied domestically due to the different work environment. Because of this, the difficult work of designing and constructing continued. The immersed tunnel work was even worse. Not only was the water deep, but the current was rough, making it the worst working condition. In particular, when connecting the fifth hull, the connection was not made for 13 days, creating a dangerous situation where the construction almost failed. However, with our own technology and perseverance, we succeeded in connecting the last hull last September, achieving a symbolic feat that raised the level of Korean construction technology by one level. ■ Concrete Concert, the world is surprised! Every day was a difficult six-year construction period. However, each time we overcame a difficult situation, a world record was set. We set five records: construction on soft ground at a depth of 48 m, the longest hull (180 m long), the world’s first double-joint hull connection, and the first immersed tunnel installed in the open sea with strong waves. It is also recognized for its safety, with an earthquake-resistant design of 8.0 and a wind-resistant design that can withstand 56 m/s. This is because the parts connecting the 22.5m pieces that make up a single ship were constructed with a double joint structure that is not affected by external environments such as earthquakes and tsunamis. Before construction, foreign construction companies that were reluctant to give us their technology are now visiting Korea to learn our technology as the opening approaches. On February 2, 2008, the weekly magazine ENR published in the United States ran a special article on Geoga Bridge under the title “Concrete Concert,” and in April and June of 2007, McDonald’s, a British construction company, visited twice to learn about Korea’s technology. Geoga Bridge has now become a symbol of Kor