The smell of rotten eggs hits us as soon as we open the camper van door. That and the steam escaping from the ground are signs that we've arrived in New Zealand's volcanic heartland.
New Zealand sits astride a major fault in the earth's crust where the Pacific continental plate is sliding under the Australian one. That accounts for the earthquakes that regularly occur and in the centre of North Island, around Rotarua and Lake Taupo, generates some intense geo-thermal activity and some bizarre landscapes. Boiling mud pools, fumaroles (vents where steam escapes from the ground), geysers, strange coloured rocks and lakes, and the cones of still active volcanoes litter the landscape. Lake Taupo, New Zealand's largest, was formed as a result of a massive eruption in 186AD that was recorded by the Chinese and the Romans.
The names reflect this vulcanism. 'Hell's Gate', Craters of the Moon', 'Kerosene (!) Creek' are just some examples. Moreover, if the names aren't enough to tell you that this is no ordinary place then the warning notices certainly will. Do not enter! Dangerous ground! Extremely dangerous! Boiling mud - stay on the path! It's enough to make the most intrepid tourist wary of coming here.
But come they do. This is the most popular destination in New Zealand. Rotorua, like Queenstown in the South, boasts just about any activity you care to mention. With the added attraction that after a hard day scaring yourself witless, you can relax in a nice hot tub.
We have come to see all this but particularly to do the Tongariro Alpine Crossing. This walk - 'the best one day walk in the world!' (New Zealand is not shy about bigging up its attractions) goes between two mountains - Mount Tongariro and Mount Nguaruhoe - crosses lava flows, crater floors, skirts active geothermal areas and lakes of emerald and blue before descending through the forest. Mount Tongariro may be dormant but Nguaruhoe last erupted in 1975. Ask a child to draw a volcano and they will draw Nguaruhoe. A perfect cone it featured as Mount Doom in the film 'Lord of the Rings'. This has had the unfortunate effect that many people now refer to it by that name rather than its Maori original. It is possible to climb it, as Kate did in 1984, but she advises against it. A 2000 foot slog up a glorified slag heap is how she describes it. Better to admire it from the bottom.
However, plenty of people are not put off and do climb it as part of the crossing. In fact, procession might be a better description. From the start at the car park at 7.30 until the finish seven hours later, we encounter a constant stream of people doing the walk. It reminds me of Snowdon on a summer Saturday. Whilst I don't see anyone in high heels (admittedly on Snowdon they had gone up on the train), I do see several people in jeans and sandals and Kate sees someone in flip-flops! - alright if the weather is fine (which today it is) but it can change very quickly here. Only a few days ago several hundred people had to be rescued from the mountain when the weather became wet and very windy. Several, I imagine, had a very uncomfortable day.
Nevertheless, today the school parties and young backpackers doing it as part of the New Zealand circuit just have a good time and like us enjoy the experience. If not the best one day walk in the world, it is certainly in the top 10.
So we could have shown you a picture of Mt Nguaruhoe (and we will when we get an internet connection that's fast enough to upload some photos) but, hey, you've all seen the film! So instead here is something even more amazing. And yes the lake really is that colour.