The Tongariro Alpine Crossing is arguably the finest one-day walk in New Zealand.
It's 18km ascends the vents of Mt Tongariro, a live volcano that forms part of
New Zealand's oldest national park. There is no water or shelter and the temperature
can change by 25degC in less than an hour. The large cone in the background is
Mt Ngaruahoe, another vent of the Tongariro complex.