It's only 6am but there are already more than a hundred people waiting for the cable car that leads from Chamonix to the top of Aiguille du Midi, in the French Alps. It is a scene that repeats here almost every day during the busy summer months. Riding in the cabin that carries passengers to the top of the 3,842m (12,604ft) peak in only 20 minutes is one of the most popular attractions in the French mountaineering capital.
A rocket-shaped structure carved into the top of this majestic peak, complete with man-made tunnels and platforms, allows visitors to marvel at spectacular views of Mont Blanc. It also serves as one of the most unusual natural laboratories in the world.
"This place is unique because it gives us easy access to a very extreme environment," says Matan Ben-Asher, a geomorphologist at the Laboratory of Environment Dynamics and Territories of the Mountain (Edytem) at University Savoie Mont Blanc, in Chambery, France, while we make our way through the tunnels to the platform above the east face of Midi. There, his colleague Josué Bock had already set three static ropes, throwing the other ends to a steep rock slope 30m (98ft) below the platform. Ignoring the numerous tourists curiously watching this procedure, the two researchers put on their helmets and climbing harnesses, load a drill and laptop into a backpack before rappelling off into the void.
They will spend the next few hours hanging from the ropes about 200m (656ft) above the glacier, maintaining part of a sensor network installed through deep boreholes into the rock walls of Aiguille du Midi. One of their tasks is to repair a broken cable that connects the electrodes of a device for measuring electrical resistivity. This expensive instrument is commonly used for the detection of water and minerals in soil, but is not built to endure the freezing temperatures and frequent lightning strikes it experiences on the rockface beneath the cable car station.