<p><strong>Encased in ice-cooled orange suits, scientists explore the Cave of Crystals, discovered a thousand feet (304 meters) below <a id="xvzo" title="Naica (map)" href="http://maps.nationalgeographic.com/map-machine#s=r&amp;c=27.85662874232211, -105.49191690981385&amp;z=13">Naica (map)</a>, <a id="ybds" title="Mexico" href="http://travel.nationalgeographic.com/travel/countries/mexico-guide/">Mexico</a>, in 2000. <a id="w8g5" title="Read full story >>" href="http://news.nationalgeographic.com/news/2010/10/101007-lost-crystal-caves-mexico-science-mine-superman-ice-palace/">Read full story &gt;&gt;</a></strong></p><p>Expeditions in 2008 and 2009 uncovered biological mysteries, parallels with other planets, and the "Ice Palace," an unexplored cavern lined with rare crystal formations, according to <a id="wr4p" title="Into the Lost Crystal Caves, a National Geographic Channel documentary to premiere Sunday" href="http://channel.nationalgeographic.com/episode/into-the-lost-crystal-caves-4636#tab-Overview"><em>Into the Lost Crystal Caves, </em>a National Geographic Channel documentary to premiere Sunday</a>. (The National Geographic Channel is part-owned by the National Geographic Society, which owns National Geographic News.)</p>

Crystal Underworld

Encased in ice-cooled orange suits, scientists explore the Cave of Crystals, discovered a thousand feet (304 meters) below Naica (map), Mexico, in 2000. Read full story >>

Expeditions in 2008 and 2009 uncovered biological mysteries, parallels with other planets, and the "Ice Palace," an unexplored cavern lined with rare crystal formations, according to Into the Lost Crystal Caves, a National Geographic Channel documentary to premiere Sunday. (The National Geographic Channel is part-owned by the National Geographic Society, which owns National Geographic News.)

Photograph courtesy Oscar Necoechea, Speleoresearch & Films/NGT

Pictures: Return to the Crystal Caves

Returning to Mexico's otherworldly Cave of Crystals, explorers have uncovered a new cavern, microscopic life-forms, and more.

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