Diamond Head State Monument offers breathtaking views overlooking the Pacific Ocean and Honolulu. In fact the view is so good, it was used by the US military as a post for preventing attacks against Honolulu.
The trail takes you to the edge of a 300,000 year old crater. While the hike isn’t that long in terms of distance, it can be somewhat challenging due to its ascent. Parts of the trail are over uneven rock, and the 99 steps near the end of the hike are steep. Also, the only water fountains are at the beginning of the trail.