 On 4 May 1994 the first physical link between Britain and France since the Ice Age was officially opened by the Queen and Francois Mitterrand, President of France.
The historic breakthrough had been made a little over three years earlier, when the two tunnels driven from each country met 40 metres below the sea bed.
But the idea of a fixed connection had been around since Napoleon, the first leader to support the building of a tunnel.
It sparked fears of invasion in Britain that continued to hold back popular and political support for a link until after World War II.
Politics and technology delayed the project becoming reality for another three decades, and the financial problems continue to this day. But there is no doubting the tunnel's status as an engineering masterpiece.

Scare stories spread after French prints depicted Napoleon's troops invading through a tunnel |
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 The opening ceremony was the culmination of eight years' work 
 The breakthrough is celebrated, 1 December 1990 |