I said it before and I'll say it again: Tongariro Alpine Crossing is an amazing hike. Unless you take either of the side tracks to Mt. Tongariro or Mt. Ngauruhoue, Red Crater at 1886m a.s.l. is the highest point on the route and provides spectacular views in all directions. Here's a look to the east, towards Emerald Lakes. On a sunny day they resemble little gems sparkling in the endless ashes. It's just over a hundred meters elevation difference between Red Crater and the lakes, but boy, it is steep! And as if the steepness wasn't enough, the descent leads through a very loose surface made up mostly of ash and hardly any bigger rocks. It must be quite challenging doing the crossing in the opposite direction.
It's quite windy up there. In fact, it was one of the strongest winds I've ever experienced. (2014-03-05 Tongariro Alpine Crossing, New Zealand)