An educational path reflecting recent events in Swiss history is the so-called Toblerone trail, leading from Bassins, in the foothills of the Jura, to Gland near Nyon on the shores of Lake Geneva.

20baladeWelcome to Switzerland in Sight - Julia Slater

Don't get the idea that the trail will guide you through the history of chocolate making; the Toblerone line had a deadly serious purpose. It was started in the end of 1930s as a line of defence against possible invasion, and derived its name from the triangular shape of the concrete anti-tank barriers that were part of the fortifications.

The historic installations along the line might well have been demolished without the intervention of a number of private individuals who wanted to ensure that the younger generations would know what life was like in wartime Switzerland. With the help of sponsors and the defence department, they have cleared a path for walkers, put in walkways and steps, cleared away some of the undergrowth and renovated some of the most interesting remains.

Two fortresses along the route have been restored to their original appearance. One is the mysterious Villa Rose (or Pink Villa), built in 1940, with false windows and 2.5 meter (7 feet) thick walls. For years it intrigued sharp-eyed travellers between Geneva and Lausanne in pre-motorway years, who noticed that although it was evidently meticulously maintained, there was never a light in its windows, and never a car in its drive... Veterans of the Swiss wartime mobilisation, however, knew that the ground floor consisted of several gun emplacements, while the basement was the sleeping and eating quarters for the troops serving there. They could remain in the villa for several periods cut off from the outside world, apart from by military telephone. No room was neglected when it came to fortifying the villa: there was a hole in the wall even of the toilet through which a hand grenade could be lobbed if necessary. The villa remained in occasional use by the military up until the end of 1994. Now, along with the other renovated fortress, it is a listed building - the first time such recent buildings have been listed in Switzerland.

You can also see traces of the original anti-tank barriers, which were built in 1936-7 with rail sections cut into lengths of just over a meter (3 feet), up-ended and driven into the ground. These defences stretched for more than 9 kilometers (just over 5 miles), although they now look very feeble in comparison with the massive toblerones.

The toblerones themselves, a second line of defence, stretch for about 10 kilometers (six miles) down to the lake shore. In all about 3,000 of them were erected, and nearly all are still there. In some places the path even snakes between them. Most of them are about human height. Many are now largely overgrown and provide an ideal habitat for a number of animals.

The line crossed some very desirable land, which could pose problems with its owners, who included the head of the Bonaparte family, Prince Louis Napoleon. The prince - who later fought with distinction in the French resistance - handed his section over without compensation. But things were more difficult with the distinguished Polish pianist and former president Ignace Paderewski, whose property in Switzerland was all he had left after his own country was invaded by the Nazis in 1939. It took until September 1940 for an arrangement to be reached with the aging musician. The government helped him move to the US, where he headed a Polish government-in-exile until his death in 1941.

Look out for flying golf balls as the toblerones, and the path, cross what is now the Domaine Imperial golf course. It might seem a strange name for a golf club in republican Switzerland, but it has a connection not only with Napoleon, but also with the Austrian imperial family. Its clubhouse is a villa built by one of Napoleon's nephews and between 1919 and 1921 it belonged to the exiled Habsburgs.

Despite the effort put into building the line over several years, the Swiss, lacking sufficient modern weaponry, and having seen the methods used on European battlefields, were under no illusion that they had built an impregnable barrier. The best they could hope for was to make the enemy pay dearly for any victory. It was considerably less obvious in 1940 than it is today that Hitler would not invade, especially after German troops had swept into neutral Belgium and neutral Norway.

The attraction of the walk is not only its unusual military history, but also its largely unspoilt surroundings, which are a paradise for nature lovers. It follows the course of three rivers, including the Promenthouse, after which the defence line was officially named. Hikers can enjoy splendid views over to the mountains on the opposite shore of Lake Geneva.

The total length of the walk is 15 km (9 miles) but less energetic visitors may prefer to confine themselves to the flatter section between Gland and Nyon, which is easily accessible by car or train. Information panels in French are being erected along this last section of the path. It is hoped that both German and English translations will be available in the future. The section from Bassins to Gland has been left free of panels, to enable hikers to enjoy the natural surroundings which have been untouched for 60 years.

Welcome to Switzerland in Sight