A hike to the famous Tour Isabelle natural double arch (also named the Tour Percée or Pierced Tower). Its span is 32 metres (105 ft), which makes it the biggest natural arch in the Alps.

It remained unknown for probably everybody, until its discovery in May 2005. 

On the verge to double arch Tour Percée

6.8 h: 11.9 km 1000 m up over 1880 m 1000 m down

• Starting point: Bus stop Plateau-des-Petites-Roches, Col de Marcieu

• Climbing up and down on the verge (just careful hiking, no equipment needed). 

• Tour Percée

• Back to the bus

To Trailhead Download Track