Hiking along a ridge on O'ahu, Hawai'i with my brother in front. Even on a cloudy day this ridge gave a spectacular view of the island. With the steep drop down on both sides of the trail, the actual danger of your position on top of that mountain- it gives you that wonderful feeling of being alive. Erosion is a big problem on many hiking trails in the world, and on O'ahu parts of trails are so eroded you really get a feel of why this is an important problem.