shadow

Swiss tunnel: Not actually the world's longest tunnel

When Swiss engineers completed drilling the Gotthard Base Tunnel Friday, they were lauded for finishing the world’s longest tunnel – but actually it's only the world's longest rail tunnel. Read on to find out what underground structures take the honors for being the longest.

Arnd Wiegmann/Reuters
A worker and a visitor stand at the construction site of the Gotthard Base Tunnel at the Erstfeld-Amsteg section, on Oct. 5.

5. Seoul Metropolitan Subway

The Seoul Metropolitan Subway's Line 5 is the longest rapid-transit line in the world right now and one of the longest tunnels, period, measuring 29.6 miles underground. The Seoul Metropolitan Subway is one of the most widely used rapid-transit systems in the world, making about 8 million trips a day between all of its lines.

1 of 5
of 5 stories this month > Get unlimited stories
You've read 5 of 5 free stories

Only $1 for your first month.

Get unlimited Monitor journalism.