How does the Internet connect between continents?...

How is the Internet shared between continents? Answer: Via submarine communications transatlantic cable, a cable laid on the sea bed between land-based stations to carry telecommunication signals across stretches of ocean. The cable is used for various sorts of telecom traffic, including the Internet. Satellites orbiting the planet also help to supplement communications, relaying signals over long distances or as backup in the event of communications failure. Cable is preferred over satellite due to the much lower latency and higher bandwidth it achieves.
The first submarine communications cables carried telegraphy traffic. Subsequent generations of cables carried first telephony traffic, then data-communications traffic.
Modern cables use optical fiber technology to carry digital payloads, which carry telephone, Internet and private data traffic. They are typically 69 millimeters (2.7 in) in diameter and weigh around 10 kilograms per metre (7 lb/ft), although thinner and lighter cables are used for deep-water sections.
As of 2010, submarine cables link all the world's continents except Antarctica.

courtesy: Nuts and bolts