Gunpowder was first used in 1679, to build an underground section of the Canal du Midi, a canal connecting the Atlantic Ocean and the Mediterranean Sea. The tunnel was 157 meters long. Nitroglycerin ...

Blasting explosives like gunpowder, nitroglycerin, and dynamite all work well for carving a tunnel through a mountain. The dense rock walls can support themselves, and they won't collapse into the ...