Programs run on computers, and computers are connected to the internet. This network was developed in the last 60 years, first to provide military data communication that is resilient to rocket attacks, before being extended to be an academic network, and later becoming a commercial network used by anyone and available almost ubiquitously all over the world.
The design of the network and research into the same started as a response to Gagarin's orbiting of the Earth in the sixties. Sending Gagarin to space and orbiting the Earth was a demonstration that Russia could send a rocket anywhere on the globe, possibly with atomic explosives. It meant that any data network that needed some central control was not resilient to such an attack. It was not feasible to have a network with a central location as a single point of failure. Therefore, research was started...