The Vercors in 4 days

Thousands of hollow straw stalactites up to 3 metres long hang over an emerald lake; the guided visit follows an underground river.

Twenty-five kilometres of road from Villard-de-Lans to Pont-en-Royans, through tunnels and along ledges above a gorge up to 700 metres deep.

Painted houses propped on timber beams over the green river, seen from the Pont Picard, with a climb to the Trois Châteaux for the view.

A road cut in 1896 into a limestone cirque 600 metres above the valley floor, with tunnels and rock windows along 4 kilometres.

A building set into the slope above Vassieux that tells the story of the Vercors maquis, its free republic of July 1944 and its destruction.

Where the Alpine Vercors turns Mediterranean: forests to the north, a 1,000-metre drop to the Drôme valley and the lavender of Die to the south.

France's largest mainland nature reserve, 17,000 hectares with no roads or villages, for days of walking among ibex, marmots and vultures.

A sheer-sided limestone block of 2,087 metres, first climbed with ladders and ropes on the orders of Charles VIII in June 1492.