2014 marks two decades since the inauguration of the Channel Tunnel, linking France and England.
On this occasion, CNN has compiled a list of the most interesting tunnels in the world, up to the wonders of modern engineering.
The Channel Tunnel, England/France
The construction that inspired the list was inaugurated twenty years ago, in 1994. Although the achievement is relatively recent, the idea of connecting the British Isles to the mainland, using a tunnel between England and France is not new.
The first proposal in this regard was made by the French engineer Albert Mathieu in 1802, more than two hundred years ago. His project involved an illuminated tunnel, traversed by carriages, and an artificial island halfway, to change horses.
The works on the current construction started in 1988. The Channel Tunnel has a length of 50 kilometers and connects the city of Folkestone, Kent, in Great Britain, to Coquelles, near Calais, in France. The average depth of the tunnel is 50 meters under the seabed, the deepest point being 75 meters.
Lærdalstunnelen as it is called by the locals joins the localities Lærdal and Aurland, in western Norway. Its construction begun in 1995 and was inaugurated five years later in 2000, and cost a little over one billion kronor, the equivalent to about 120 million euro. Lærdal has a length of 24.5 kilometers and is the longest road tunnel in the world, surpassing Zhongnanshan and Jinpingshan, in China and the famous St. Gotthard in Switzerland.
The construction linking the towns Kawasaki, Kanagawa Prefecture, and Kisarazu, Chiba Prefecture, is a bridge-tunnel hybrid, which helps crossing the Tokyo Bay. Inaugurated in 1997, after nine years of construction and 23 years of planning, it reduced the journey time between the two cities from one hour and a half to 15 minutes. The total project costs are amounted to 1.44 trillion yen, about 10 million euro.
The total length of 14 km, is crossed on a bridge for the first 4.4 kilometers, and then through an underwater tunnel for the final portion of 9.6 kilometers. The two constructions meet on the artificial island Umihotaru, where drivers can stop and visit the stores and restaurants built there. The tunnel is ventilated with tower Kaze No To that seems to rise from the waters of the bay.
Officially called Eisenhower-Johnson Memorial Tunnel, it is located 80 km from the city of Denver and shortens the route of the highway I-70, when passing through the Rocky Mountains. Located 3,400 meters above the sea level, Eisenhower is the longest mountain tunnel and the highest point of the Interstate road system , in the United States, and also one of the tunnels a the highest altitude in the world.
The first section was opened in 1973 and the second, six years later, in 1979, the tunnel spanning 2.7 kilometers.
The impressive construction inaugurated in 1961, spans 1.7 km and includes six spectacular spirals that lead to an observation point located in the industrial city of Drammen, Buskerud, in Norway.
Opened by King Olaf the fifth in 1961, Spiralen is located between 50 and 213 meters above the sea level. The observation point, located near Drammen, offers a stunning view and has a museum, a terrace and restaurants.
Before the construction of this impressive tunnel, the only way to get to Guoliang village was along a path carved into the rock, in the Taihang Mountains. In 1972, thirteen villagers led by Shen Mingxin decided to build a tunnel and began the excavations manually. Three of them died before the completion of the work, and the construction transformed the village and became a major tourist attraction, which constantly attracts visitors to the area.
Located in Henan Province, in eastern China, the tunnel spans 1.2 kilometers and has a width of only four meters. Guoliang was opened for traffic on May 1, 1977, after only five years of construction.
Started in 2003 and inaugurated in 2007, SMART tunnel is one of the most important projects of the Asian government. With a dual function of road tunnel and drainage channel in case of flooding, SMART was developed to limit the damages during frequent floods in Malaysia.
The construction cost the Malaysian authorities about 400 million euro, but since its inauguration in 2007, flood-prone areas like Masjid Jamek, Dataran Merdeka, Leboh Ampang or Jalan Melaka, were protected from the fury of nature. The drainage channel has a length of 9.7 km, while the road tunnel spans 4 kilometers and connects to Simpang airport.
The tunnel connecting Bund to Pudong, under Huangpu River, is one of the tourist attractions in Shanghai. Initially, it was designed as a pedestrian tunnel equipped with a moving walkway. Currently, the passengers are transported by means of automatic wagons and the interior of the tunnel is lit by neon lights, which, along with the sounds from the speakers, provide psychedelic effects.
The length of the Bung tunnel is only 646 meters and the cost of a ticket is twenty times higher that the ferry that crosses the Huangpu River.
Seikan tunnel was built in order to connect Aomori Prefecture located on the island of Honshu, to Hakkaido Island, in northern Japan. This tunnel has significantly shortened the journey. The train tracks are 240 meters below the sea level and at 100 meters under the sea bed, so Seikan is the rail tunnel found at the deepest point, in the world. Seikan spans 53.8 km, being the longest railway tunnel in the world, until the completion of the Gotthard tunnel (its longest section will be 57.1 kilometers).