Gargantua

Gargantua is a limestone cave located on the Andy Good Plateau in Alberta and British Columbia, Canada. As of 2002 it has 6,001 metres (19, 688 ft) of passages with a depth of 286 metres (938 ft). It contains the largest natural cavern in Canada at 290 metres (950 ft) long, 30 metres (98 ft) wide and 25 metres (82 ft) high. In October 2002, a group of caving club students from W. R. Myers High School were trapped in the cave overnight, after failing to break through the waterfall exit.

Cave data from Wikidata (CC0). Summary from Wikipedia (CC BY-SA).