Northeast of Honolulu on Oahu, the Haiku Trail climbs 2,000 feet up through forest on the slopes of the Koolau Mountain range. There are 3,500 metal steps built in the lush cliff heading up to a vista of the Haiku Valley.
Note: the trailhead may be closed. A local private land order near the trailhead has been causing some problems
Here are some notes on adventuring in Hawaii. First, unlike mainland forests, the tropical island forests can grow very dense and can mask dropoffs. Plus, the trails can be very wet and slick most of the year (December to February is the main rainy season, but expect rain all year round). Stay on the trail to avoid disorientation. Second, speaking of disorientation, be aware that most Hawaiian topographic maps use the Old Hawaiian Datum. When trying to use the latitude/longitude from those maps with a GPS unit, you will think you are 0.4 miles south/southeast of where you really are. Kind of important in a dense jungle. Third, the bacteria Leptospirosis is found in the local waters and mud. It causes flu like symptoms within 2-20 days of contact, and can be fatal if not treated with antibiotics. Fourth, when hiking about, walking sticks can be very helpful for stablity in the slick conditions, for probing mud hole depths and clearing webs of the tiny crab spider.
Overall, Haiku Trail is the 30th most popular hiking trail of all 45 hikes in Hawaii.