6) Wai-O-Tapu, New Zealand
Covering an area of about seven square miles on the border of the Rotorua-Taupo main highway, Wai-O-Tapu has the hallmarks of a harsh, inhospitable alien real: bursting bubbles of mud and bright orange, yellow, and green swaths enshrouded in steamy mists. It is brimming with sulfur, antimony, ferrous salt, and alum, which are attributable for its yellowish, orange, greenish, and brownish colors. This geothermal wonderland occupies the site of what was formerly hailed as New Zealand’s largest mud volcano, whose original cone, present until 1925, is now eroded. Photo credit.