Grenchen (French: Granges) is a municipality in the district of Lebern in the canton of Solothurn in Switzerland. It is located at the foot of the Jura mountains between Solothurn and Biel. With over 16,000 inhabitants, it is one of the larger towns of the canton of Solothurn. The city is well known for its watch industry, that has been present for more than 150 years. Although Grenchen is a small city, it has its own airfield with facilities for the transport of goods. It is mostly used by private pilots and parachutists, but also for business travel. The freeway A5 and a connection to Grenchen lie in the vicinity of the airport. Two railway stations (Grenchen North on the Basel-Biel line and Grenchen South on the Geneva-Zurich line) provide for an excellent connection of the city on the rail network. The Grenchen Tunnel, an 8.5 km long railroad tunnel that was built between 1911 and 1915, offers a connection between the Swiss plateau and Delémont/Basel. Construction of the tunnel attracted many foreign workers to Grenchen, coming mostly from Italy.