Diamond Head Crater
The massive 760-foot crater Le'ahi got its nickname, Diamond Head, from 19th Century sailors who mistook the worthless but sparkly calcite crystals within to be actual diamonds. The would-be prospectors didn’t strike it rich, but the crater went on to become Hawaii’s most well-known natural landmark. It was formed sometime between 200,000 – 300,000 years ago when a cinder cone volcano blew its top, sending tons of ash into the air which cemented over time to become the crater. A steep trail takes you to Le'ahi’s summit where you’ll enjoy terrific views of the coastline as well as see a lighthouse, fire station, and military bunkers—all built during the early 1900s.