The Mont-Blanc Tunnel will be closed from next week until the middle of December.
The closure is to allow for major renovation – there will be further closures next year.
The company says it has deliberately chosen this time of year as tunnel usage is the lowest.
The autoroute heading to the tunnel will also be closed to allow for work to be carried out.
The tunnel carries 5,000 cars a day at peak times and was first opened in 1959.
Heat to stay for now
The heatwave alert has been extended until Thursday, with temperatures set to climb as high as 37 degrees in some areas.
Growing anger over World Cup red card
The Swiss team's manager, Murat Yakin has called Breel Embolo's red card 'unacceptable', as anger builds over the refereeing of Switzerland's World Cup quarter-final loss to Argentina.
Fire damages trees in the Jardin Anglais
A fire tore through part of Geneva's Jardin Anglais on Saturday morning, gutting several trees and damaging a lakeside building used by the Mouettes ferry service.
Cows sweltering in the heat
The heat is now hitting the country's dairy herds, with cows producing less milk as they burn extra energy to stay cool.
Lake Geneva nudists fight for their lake section
A hidden stretch of Lake Geneva shoreline has become the focus of a long-running battle over public nudity.
Holiday makers seek more than the sun
Nearly half of Swiss holidaymakers are choosing to learn a new skill on their summer break rather than simply lie on a beach.
