In a Wi-Fi world, the internet is a fleeting, invisible force which links together all of our devices. Smartphones to desktops, futuristic fridges to television sets, everything is connected together without wires. But on a global scale, this is simply not true. When it comes to communicating between London and Hong Kong, the information sent to your router might be wireless but from then on in, a series of interconnected cables transports everything across the world. The internet, in reality, is made possible thanks to the huge volume of underwater cables. While most assume that satellites are doing the heavy lifting, the bulk of information is sent along wired connections. This is far cheaper and simpler than beaming data to space, a tool usually reserved for broadcasting. The fibre-optics which make our internet a reality are buried deep in the sea bed. They serve each and every continent, spread out like a submarine spider’s web. While the current crop of cables can carry a huge amount of data, our appetite is growing, as is a need for a fall back option should anything break. The layout is designed to avoid fault zones which exist underwater and to deliver internet with the minimum amount of interference. There are issues, however, three quarters of which are down to external aggression (fishing, anchors from ships). Geological issues also pose a threat, with landslides, earthquakes and the moving tectonic plates all destabilising connections. The 2011 Tsunami which struck Japan, for example, required quick work and rerouting in order to keep the country online. The more cables which route into the country, the better protected they are in such circumstances. Not all cables are created equal, with those found in the Atlantic capable of transmitting more data than those which run down the coast of East Africa. Demand dictates performance and smaller markets lead to lower capacities in certain areas. The cables which cross the largest oceans can cost hundreds of millions of dollars. With the majority of landmasses connected, island nations and remote communities are still waiting for integration. The main challenge now is maintenance. For those in western countries, the amount of connections provides almost seamless service. For locations such as Bangladesh, one cable going down can have a big impact. Additional connections, such as the large cable nearing completion between the USA and Mexico, will add further capacity in certain areas. As internet traffic increases and bandwidth is ever more important, scaling the solutions already in place will be essential.