Stare up at constellations of glowworms on an underground boat ride. First described in Māori stories, this 200m-long cave system was lost in time until it was 'rediscovered' in 1948. Its sculpted rocks, waterfalls and whirlpools are impressive by themselves, but the bluish sparkle of glowworms, peculiar territorial larvae who lure prey with their come-hither lights, is the main draw. The caves can only be reached by a 2¼-hour guided tour with Real Journeys, departing from its office on Lakefront Dr.