As reported by International Business Times: You can hardly walk through a café, subway station or even a public park without picking up on your smartphone. Almost anywhere you turn, there’s a network to greet you. But there’s one spot the mobile Web can’t go: underwater.
A prime example of the limitations of underwater communications is the robotic vehicle sent down to explore the wreckage of the Titanic. The vehicle needed a very heavy and expensive cable attached to it in order to communicate with a boat 12,500 feet, or about 2.4 miles, above it.