Castleguard Cave is rife with superlatives. It’s the longest cave system in Canada at 13 miles (21 kilometers), as well as the only non-ice cave that sits beneath a current glacier, called the Columbia Icefield, which is the largest ice mass left in the Rocky Mountains. The result is a grand subterranean world that combines both cave and glacier attributes in a combo hardly seen before. In addition to calcium stalactites, stalagmites, and long soda straws, the cave also hosts extremely rare cave pearls, which are like spheres of calcium…
