The Channel Tunnel (or Chunnel) linking Great Britain and France has long been proposed - all the way back to the Napoleonic Era. In 1997 the Chunnel was finally opened for the first time and people can now zip back and forth from Britain to Europe via rail.

Just a short distance away is the city of London which is known to have one of the largest and most mysterious tunnel networks in the world - many of them remain secret. While many of these tunnels are off-limits or are still classified, there special tours of some of London's abandoned Tube stations.

The British Isles and Their Tunnels

Today the Chunnel is the longest undersea tunnel in the world stretching for some 31 miles. It carries tens of millions of passengers annually and millions of trucks. It functions as a rail-based shuttle service (former British Prime Minister Margaret Thatcher liked the idea of having a road tunnel and not a railway). But there was concern about what would happen if there was a major car pileup 15 miles out to sea. The chunnel is one of the greatest engineering feats of modern times.

  • Longest: The Chunnel Is The Longest Undersea Tunnel in the World

While the Chunnel is the first such tunnel to be realized connecting the British Isles with elsewhere, there have been a number of other proposed links. These include linking the island of Orkney with the Scottish mainland, a tunnel between the Republic of Ireland and Wales, and a tunnel between Northern Ireland and Scotland.

  • Welsh-Irish Link: Mulled In 2014 (Would Be Twice The Length of The Chunnel)
  • Scottish-Irish Tunnel: Proposed in 2021

But the modern Channel Tunnel wasn't the first time the Channel had been attempted. Engineers had attempted to dig the Chunnel by hand way back in 1880 and the tunnels they started can still be seen today.

Related: Discover The Rabbit Warren Of The Military Tunnels Of Gibraltar

This venture began in the golden age of railways and understandably as railways revolutionized travel and boomed everywhere in the world, there was the vision to connect the continent with Great Britain.

The first attempt to build the chunnel happened a century before the modern Chunnel got underway. In 1880 work started on experimental tunnels at the base of Abbot's Cliff in southwestern England. Even by then, the idea of an English Channel tunnel had been spoken of for 80 years.

  • Napoleon Bonaparte: Supported The Idea of a Tunnel Linking England

There was even an Anglo-French protocol in 1876 that called for a railway tunnel under the Channel.

In 1880 No.1 shaft was sunk in a 7-foot diameter pilot tunnel. In 1881, work shifted from the No.1 shaft at Abbot's Cliff to a 160-foot No. 2 shaft at Shakespeare Cliff. The plan was to meet up with the French pilot tunnel that was burrowing its way from Sangatte.

  • Two Directions: The French and British Both Began Their Tunnels Planning To Meet-Up in The Middle

While in some places, the workers labored away with hand tools, they also had an ingenious early tunnel boring machine. This contraption worked with compressed air in the motor forcing the rotary head into action chipping away at the rock.

Related: These Roman Tunnels Were Once The Longest Of The Ancient World

Abandonment and The Tunnels Today

As the modern Chunnel was dug, it even intersected with the old, abandoned 1880s tunnel. It was surreal to see how the modern tunnel compared to its century-old cousin.

But in 1882 the workers laid down their tools as the government called the whole project off out of fear of military complications of having a land link to Europe. In the end, three shafts had been drilled. Both shafts were later backfilled.

In the end, the following shafts were dug.

  • Shakespeare Cliff: 2,040 Yards
  • Abbot's Cliff: 897 Yards
  • French Side: 1,825 Yards

But one of the main reasons why it never happened (as well as technical challenges) was that Great Britain had long been at war with Europeans - especially the French. They feared it would undermine their national security.

One man, Sir Edward Watkin, even suggested that in the event of a war, the tunnel should be rigged. The entrance to the tunnel could be made to collapse with a mine wired to a button - with that button even as far away as London.

"Deep inside the warren, the aging tubes carved out by the boring machine are mostly featureless, though there is one piece of Victorian graffiti scratched into the rock: “THIS TUNNEL WAS BEGUNUG N [sic] in 1880” – signed “WILLIAM SHARP”.

BBC

These abandoned tunnels have been described as looking like old tin mines with low wooden beams. They are said to look more like mines than what one would need for international undersea tunnel travel.

Next: What You Need To Know About Seeing The Sealed Up Freight Tunnels Under Chicago