Here we see an illustration from English science fiction pioneer H.G. Wells' 1908 novel "The War in the Air." The work is best remembered today for its prophetic predictions regarding air warfare and the coming world war, but it also features this vision of a monorail spanning the English Channel between Britain and France. This was 86 years before the Channel Tunnel or Chunnel opened in 1994, enabling ground transport between the UK and mainland Europe.
But of course the idea of channel tunnel dates back to at least the early 1800s, and a channel-spanning suspension bridge proposal was submitted to Margret Thatcher's government in 1981, five years before work began on the Chunnel.