<P> In 1890, Pierre Janssen, an astronomer and the director of the Meudon astrophysical observatory, considered the construction of an observatory at the summit of Mont Blanc . Gustave Eiffel agreed to take on the project, provided he could build on a rock foundation, if found at a depth of less than 12 m (39 ft) below the ice . In 1891, the Swiss surveyor Imfeld dug two 23 m (75 ft) long horizontal tunnels 12 m (39 ft) below the ice summit but found nothing solid . Consequently, the Eiffel project was abandoned . </P> <P> Despite this, the observatory was built in 1893 . During the cold wave of January 1893, a temperature of − 43 ° C (− 45 ° F) was recorded on Mont Blanc, being the lowest ever recorded there . </P> <P> Levers attached to the ice supported the observatory . This worked to some extent until 1906, when the building started leaning heavily . The movement of the levers corrected the lean slightly, but three years later (two years after Janssen's death), a crevasse started opening under the observatory . It was abandoned . Eventually the building fell, and only the tower could be saved in extremis . </P> <P> The mountain was the scene of two fatal air crashes; Air India Flight 245 in 1950 and Air India Flight 101 in 1966 . Both planes were approaching Geneva airport and the pilots miscalculated their descent; 48 and 117 people, respectively, died . The latter passengers included nuclear scientist Homi J. Bhabha, known as the "father" of India's nuclear programme . </P>

The mont blanc mountain is the highest mountain in the alpine region