The unique profile of Diamond Head (Lē‘ahi) sits prominently near the eastern edge of Waikiki’s coastline. Hawaii’s most recognized landmark is known for its historic hiking trail, stunning coastal views, and military history. Diamond Head State Monument encompasses over 475 acres, including the interior and outer slopes of the crater.
This broad, saucer-shaped crater was formed about 300,000 years ago during a single, explosive eruption that sent ash and fine particles in the air. As these materials settled, they cemented together into a rock called tuff, creating the crater, and which is visible from the trail in the park. Most of the vegetation and birds were introduced in the late 1800s to early 1900s.
http://dlnr.hawaii.gov/dsp/parks/oahu/diamond-head-state-monument/
