A geothermal sulfurous pool in New Zealand.
The rancid Tarn of Cthok was a vast, shallow pond filled with oily-looking sulfurous water that really stank. It was all that was left of the sea that used to be there, before the War of the Gods. It would have dried out, but it was fed by underground springs. Its surface steamed the icy air and the wisps of steam carried the stench.