Did you know?
Ninety-nine percent of international data is transmitted by wires at the bottom of the ocean called submarine communications cables. In total, they are hundreds of thousands of miles long and are laid down at different depths. For example, the deepest part of the submarine cable between Japan and the U.S. is about 8,000 meters below sea level which is about the height of Mt. Everest.
The cables are installed by special boats called cable-layers. The process of laying the cables is complex—the cables must generally be run across flat surfaces of the ocean floor, and care is taken to avoid coral reefs, sunken ships, fish beds, and other ecological habitats and general obstructions.
The diameter of submarine cable used in shallow sea areas are larger than those used in deep sea areas so that the cable won't break if it comes into contact with an obstacle, like a ship’s anchor. There’s not much going on in the deep sea, so there’s less need for galvanized shielding wire. Cables located at shallow depths are buried beneath the ocean floor using high pressure water jets.
Though prices for installation change depending on total length and destination, running a cable across the ocean invariably costs hundreds of millions of dollars-the last cable laid across the Pacific cost $300 million.