New Zealand, North Island-209
The amazingly coloured Champagne Pool at Wai O Tapu near Rotorua. The orange ring round the edge is caused by the water, cooling from 74 degrees centigrade (around 180 degrees farenheit) depositing Arsenic and Antimony Sulphur Compounds. Rotorua is the most geothermically active place in New Zealand. The town stinks of eggs due to the sulphur and even the crumiest hostel has a natural hot spa!