These are photos of Orakei Korako, the Hidden Valley. (Hubby can't say it without lowering his voice, saying it slowly and adding drums, ala 2001 oddessy.)
"From earliest times, the Waikato Valley near Orakei Korako was occupied by Maori of the Ngati Tahu sub-tribe Tuwharetoa.
By the early 1800’s, the Maori population had congregated at Orakei Korako, attracted by the hot springs.
“O” is the place of “rakei” adornment. “Korako” meaning white, describing the glittering (sinter) flat.
A diary entry for the 11 March 1850 recorded that the Maoris lived in this spot “to spare their woman the trouble of procuring wood for fuel. They seldom light a fire; everything is cooked in the springs.” from:
http://www.orakeikorako.co.nz/Presentation/PresentationPic1WideSwap.aspx?ID=7748
Enjoy.
The orangey yellow color is not iron or sulfur. It's algae, according to a tour guide from just down the road a piece.
I'm amazed that so much greenery thrives so closely to the boiling water.
Click here for another link for information.