In the old days, the only reliable way to send messages over long distances was to dispatch a horse-riding messenger or a homing pigeon - until the arrival of the electrical telegraph. But fifty years before there was another kind of telegraph in Europe - the optical variety, based on the same principle of flag waving that the Navy still use today. It was called the semaphore, and relics of this amazingly efficient 19th century network can still be found around Europe.
The semaphore was the first successful and large-scale communication network that allowed transmission of messages faster than horse-riding messengers could carry. Indeed, the very word 'telegraph,' which means distance writing, in Greek, was coined to describe this nationwide network of semaphores.