Swiss engineers have blasted through the last few metres of rock to complete a new Alpine rail tunnel that could change the face of European transport.
The tunnel should be open to rail traffic within two years
The Loetschberg tunnel is 34km (21 miles) long, and runs on a route from Germany to the north of Italy.
It is the longest tunnel in the Alps and third-longest in the world.
Switzerland acts as one of Europe's major junctions for freight and the tunnel is meant to move cargo off the roads and onto rail.
More than 4,000 heavy lorries cross the Swiss Alps by road every day, leading to traffic jams, air pollution and accidents.
Eleven people died in the Gotthard road tunnel when a lorry caught fire there three-and-a-half years ago.
On Thursday morning, at the northern end of the new Loetschberg tunnel near Mitholz, an engineer blew three warning blasts on a horn before an explosion that tore away the final section of rock.
"With the breakthrough we have carved out the mountain for all to see," said Moritz Leuenberger, Switzerland's transport minister. "We are moving on."
The Swiss rail tunnel project - including a second, parallel tunnel, due for completion in 2015 - is one of the biggest engineering projects in the world. Millions of tonnes of rock have to be shifted.
The tunnels will create a route beneath Europe's natural north-south barrier, the Alps.
The second rail route, the Gotthard rail tunnel, will measure 60km - making it the longest in the world - and will cut the travel time from Zurich to Milan down to only two-and-a-half hours.
But, at a cost of more than $13bn, the project is well over budget and there are safety questions.
Eleven people have been killed during construction so far and while the Loetschberg is scheduled to open in 2007, the Gotthard will not be ready for 10 years.
SWITZERLAND: KEY RAIL TUNNEL PROJECTS
Twin tunnels being built as part of policy to move road freight to rail
Loetschberg base tunnel (Frutigen-Raron) due to open in 2007
New Gotthard tunnel due to go into operation in 2015
Combined construction costs currently put at more than $13bn