A trained botanist, Joseph Vallot (1854-1925) was a multidisciplinary scientist who first visited Chamonix in 1875 and climbed Mont Blanc in 1880. In 1887, to prove that it was possible to live at high altitudes, he spent three days in a tent at the summit. In 1890 he built an observatory-hut near the apex, at 4,362 metres, in order to conduct different experiments. The observatory was renovated and rebuilt by 1898. Vallot continued conducting his scientific visits until 1920.