This amazing natural site is also a paleontological treasure house. Seen from above, it’s a deep, circular sinkhole, possibly formed by the collapse of an oceanfront blowhole. Scramble through the three-foot-high crawlspace at its base to reach a ‘lost world’ where a sand-floored cave holds what’s arguably the richest fossil record in the Hawaiian islands. Excavations since 1996 have provided evidence of the widespread extinction of native plants and animals since Hawaii was first settled by humans.
Volunteers are on hand daily in the cave itself to explain the full story, while a walking trail follows the rim of the sinkhole up above. The reserve is also being extensively replanted with native species, and an enclave has even been populated with giant tortoises. Their sharp beaks are thought to mimic the grazing action of the flightless birds that once lived here.
Reach the reserve either by hiking along the Maha‘ulepu Heritage Trail, or driving along the dirt road beyond the Grand Hyatt, following signs for a total of 2.2 miles.