Waitomo is a little village on the North Island of New Zealand. I don’t think anybody who’s been there would disagree with me when I say that, above ground, the village doesn’t have much going for it. Nah, all the fun is to be had about 30 metres beneath the surface. Waitomo Caves are an extensive tangle of tunnels and caverns and rivers that are jumbled and ragged like the London Underground’s Neanderthal ancestor.