Bivacco Gervasutti is a cabin perched on a cliff above the Frebouze Glacier in Mont Blanc, Italy. It's made from a steel tube and has 12 bunk beds. Solar panels provide electricity to power the range and a computer for emergencies.
A bed in the cabin, which is operated by the Club Alpino Italiano, costs $14 a night, and is booked on the honor system, as the cabin has no staff. The last part of the hike requires pulling oneself up by a rope that's bolted into the rock face.
In this video, two people hike up the mountain and stay a night in the cabin. It looks very cozy.