Karangahake Gorge is a beautiful area of steep hills south of the Coromandel Peninsula, covered in native bush and divided by the winding Waitawheta river. There are old railway tracks and mining tunnels you can follow and everywhere the rusty remains of pipes and other constructions peek through the rocks.
I definitely want to do one of the walkways when I'm there again.
We were there for the climbing - which gets you to even better views of the gorge on top of the cliffs!
We only managed one climb, though, because our map (and our orientation :) led us through the bush for more than an hour before we actually found the rock - and after the first climb it started raining. We were warned that this is the wettest spot in the North Island :)
Still it was beautiful and I'm looking forward to go there again!