The internet isn't in the cloud. It's at the bottom of the sea.
Almost all data travelling between continents, including your video calls, bank transfers and messages, runs through fibre-optic cables on the seabed. Some are barely thicker than a garden hose. Satellites carry only a small share. The cloud is mostly glass lying in the dark.
When you send a message from London to New York, it almost certainly does not go to space. It travels as pulses of light through fibre-optic cables laid across the floor of the Atlantic. Several hundred submarine cables span the world's oceans, and they carry the overwhelming majority of intercontinental internet traffic.
In the deep ocean, a cable can be about as thick as a garden hose: hair-thin glass fibres at the centre, surrounded by copper, steel wire and plastic. Near the shore, where anchors and fishing trawlers pose a danger, cables are heavily armoured and often buried in the seabed. Modern cables can carry hundreds of terabits per second.
The idea is older than you might think. The first transatlantic telegraph cable was completed in 1858; it failed within weeks, but a durable link followed in 1866. Laying cable is still done by specialised ships that pay it out across thousands of kilometres, guided by detailed surveys of the seabed.
Cables break more often than most people realise, well over a hundred times a year, usually because of ships' anchors, fishing gear or undersea landslides. Repair ships grapple the cable up from the depths and splice it. Because so much depends on them, cables have become a matter of national security, and more are now being built by large technology companies themselves.
Source: Wikipedia — Submarine communications cable · Text summarised from Wikipedia (CC BY-SA 4.0)
