A hill
All but two of our group's regular hikes involve an uphill section before the official turn-around (turning around unofficially is not frowned upon). Here is the one on Kulanaʻahane. Two unrecognizable hikers ahead.
The Kulanaʻahane Trail part of the hike isn't much more than a mile-and-a-half long, but it climbs from a bit over 600 feet to almost 1800 (according to my not-too-trustworthy GPS), most of it on this last little bit.