Simplon

[sim-plon; French san-plawn]

noun

a mountain pass in S Switzerland, in the Lepontine Alps: crossed by a carriage road constructed 1800–06 on Napoleon's orders. 6592 feet (2010 meters) high.
a tunnel between Switzerland and Italy, NE of the Simplon Pass: longest tunnel in the world. 12¼ miles (20 km) long.

Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018

Examples from the Web for simplon

Truly now—you hated the whole idea of driving over the Simplon.
The Market-Place
Harold Frederic
Among these marvels is the Simplon Tunnel, famous the world over.
Steve and the Steam Engine
Sara Ware Bassett
The Simplon tunnel is the longest in the world, being 12-1/2 miles long.
From Pole to Pole
Sven Anders Hedin
That would be a glorious route to the Simplon tunnel and Italy!
More Science From an Easy Chair
Sir E. Ray (Edwin Ray) Lankester
Left the Simplon in torrents of rain, which lasted the whole day.
The Greville Memoirs
Charles C. F. Greville