Mt Ngauruhoe 2,291m (7,516 ft), North Island, New Zealand.
Tongariro National Park.
Not the most beautiful landscape to look at, unless your a geologist. In which case this is beautiful. You can make out two people standing on the lefthand side of the rim on the other side for a bit of scale. Its one big hole.
Below is the the angle of the slope we were climbing, a good 45 degree angle.