Story highlights Gotthard tunnel's length overtakes Japan's Seikan Tunnel and the Channel Tunnel

Leaders of Germany, France and Italy were on hand for opening ceremonies

(CNN) Seventeen years after construction crews started boring beneath the Swiss Alps, the world's longest, deepest tunnel officially opened Wednesday.

Fittingly for a project billed as Switzerland's "construction of the century," the Gotthard Base Tunnel was inaugurated amid colorful, sometimes surreal scenes, with visiting dignitaries treated to costumed dancers, fireworks and plenty of yodeling and alphorns.

Photos: World's longest tunnel opens under Swiss Alps Artists perform during the grand opening for the tunnel, the world's longest and deepest rail tunnel. Hide Caption 1 of 7 Photos: World's longest tunnel opens under Swiss Alps The 57km (35-mile) tunnel, which runs under the Swiss Alps, was first conceived in sketch-form in 1947. Construction began 17 years ago. Hide Caption 2 of 7 Photos: World's longest tunnel opens under Swiss Alps Artists perform during the grand opening of the tunnel. Hide Caption 3 of 7 Photos: World's longest tunnel opens under Swiss Alps A horse-drawn carriage parades during the opening of the tunnel. Hide Caption 4 of 7 Photos: World's longest tunnel opens under Swiss Alps From left to right, Italian PM Matteo Renzi, Swiss President Johann Schneider-Ammann, Germany Chancellor Angela Merkel and French President Francois Hollande on board the maiden voyage on the line. Hide Caption 5 of 7 Photos: World's longest tunnel opens under Swiss Alps A guest poses with an umbrella decorated with the Swiss Rail clock logo before the opening ceremony of the Gotthard Base Tunnel. Hide Caption 6 of 7 Photos: World's longest tunnel opens under Swiss Alps The first train comes out of the tunnel in Erstfeld. Hide Caption 7 of 7

European leaders including German Chancellor Angela Merkel, French President Francois Hollande and Italian Prime Minister Matteo Renzi joined Swiss President Johann Schneider-Ammann on the first official journey on the line.

The 57-kilometer long (35-mile long) tunnel creates a high-speed rail link deep beneath the famous mountain range, connecting northern and southern Europe.

And with characteristic Swiss punctuality, this major engineering feat has been completed on schedule.

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