When we stream the latest TV series, or download high-resolution photos, we are probably unaware that the data behind them is speeding around the world in cables under the sea.These cable systems, faster and cheaper than satellites, carry most of the intercontinental Internet traffic. Today, there are over 420 submarine cables 16 , stretching over 700,000 miles around the world. It is not a new phenomenon, 17 . The first transcontinental cable—laid in 1854—ran from Ireland to Newfoundland, and made telegraph communication possible between England and Canada. Currently, the world’s highest-capacity undersea Internet cable is a 5,600-mile link between the US and Japan. 18 named “FASTER,” the cable connects Oregon in the US with Japan and Taiwan.The submarine cables require extra 19 to install. They must generally be run across flat surfaces of the ocean floor, and stay clear of coral reefs, sunken ships, fish beds, and other general 20 . The fiber-optic cables are also very fragile, so they are surrounded with layers of tubing and steel to prevent damage.
16.
(A) at large
(B) in service
(C) by contrast
(D) under control