In 1892 a hidden lake trapped inside a glacier on the French side of Mont Blanc suddenly burst and inundated the populated valley below in the greatest natural disaster ever recorded in the Alps. No one knows if a similar cataclysm is now imminent. NOVA ventures deep inside the glacier itself to find out and explores a uniquely beautiful and dangerous environment with a new breed of explorer known as the “glacionaut.” “Descent Into the Ice” is the latest installment in NOVA’s High Adventure serieswhich has already taken viewers to the tallest mountains in Asia, Antarctica, and Africa, and now probes Mont Blanc, the highest point in western Europe. The program is a Journey to the Center of the Earth style voyage into the eerie inner world of glacial cracks, crevasses, ice shafts, pits, water wells, and tunnels, as glacionauts search for evidence of hidden lakes that form through the intricate action of melting ice. Mont Blanc is French for “white mountainan apt name for the snow covered peak rimmed by massive glaciers that formed 10,000 years ago during the last ice age. The glaciers have been slowly melting ever since, creating a labyrinth of ice caves and concealed lakes that threaten all who live downslope. On July 12,1892, 200 vacationers and residents of the Alpine town of Saint Gervais died when one of these lakes suddenly and catastrophically emptied, sending a tidal wave of water plunging down the narrow gorge onto the sleeping villagers. Because the lakes form deep within the glaciers, they are virtually undetectable except by those willing to descend the shafts, called water wells, that feed meltwater into a maze of natural features threading their way to concealed caverns. NOVA’s cameras accompany French glaciologist Luc Moreau and German photographer and adventurer Carsten Peter as they probe Mont Blanc’s thousand foot thick Mer de Glace (“Sea of Ice”) as well as the mountain’s Argentiere Glacierthe second largest glacier in France. At various stages, Moreau and Peter rappel, climb, raft, and scuba dive through the icy wilderness. The underwater dive is the first ever on Mont Blanc, a bone chilling experience made all the more perilous when the breathing apparatus freezes. Members of the scientific team also resort to a century old technique to measure the speed of water flow within the glacier. By introducing a potent dye at the top, they can determine the time it takes for the color to reach the bottom, allowing the glacionauts to fill in the picture of what exactly is happening on the inside.