ALPS-A glass box perched on the edge of a French mountain nearly 4,000m (13,123ft) above sea level is to open to the public on Saturday. ‘Step into the Void’ stands over a sheer drop of more than 1,000m and offers views of the European Union’s tallest mountain, Mont Blanc.

The box can withstand winds of more than 137mph (220km/h) and is made of three layers of tempered glass fixed to a support structure.

Tourists must set off from Chamonix and take two cable cars to reach the attraction at the top of the Aiguille du Midi mountain. Entry to the ‘void’ is included in the ?55 (£46) return fare.

The Grand Canyon, in Arizona, opened a similar attraction in 2007.

The Skywalk juts out 21m (70ft) from a cliff edge and is 1,220m (4,000ft) above the canyon floor. :: Watch Sky News live on television, on Sky channel 501, Virgin Media channel 602, Freeview channel 82 and Freesat channel 202.