Diamond Head sits on top of a much larger volcano, called Koolau, that together with a second large volcano called Waianae forms most of Oahu’s land mass. The Koolau and Waianae volcanoes are ...

The Ko'olau Mountains are what remain from a volcano that erupted over 2 million years ago, with the mountains being one of two that make up the island of Oahu. Aside from a peaceful opportunity ...