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One of Martyn's diving companions, Robbie Schmittner, in a huge flooded cave in Mexico. 公仔箱論壇: h) v- L9 L: F: c2 ^2 M" }: X' n
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Divers carry remote underwater flash guns to illuminate this image, taken in what is probably the world's biggest underwater tunnel, Weebubbie Cave beneath the remote Nullarbor Plain of western Australia.5.39.217.77( \& B, _: `, e8 q8 C1 o# v
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1 F2 ~! P" d$ u) [# n, ]公仔箱論壇Divers often use guide-lines to keep them on track in the murky depths. Getting lost can be fatal.tvb now,tvbnow,bttvb; ]( k+ R( \! x" y6 b! _% f3 Q
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Deep and dark doesn't always mean cold: Jenny Pinder swims through the underwater passages of the Grotta Giusti Cave in Tuscany, Italy. where geothermal activity heats the water to an amazing 35 degrees centigrade公仔箱論壇 o9 N+ ^) m# b# F7 g
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; q1 M( `+ F9 y2 v$ O4 [tvb now,tvbnow,bttvbIn another of Martyn's photos Helen Rider swims through the narrow confines of Taina Cave near Santo Domingo in the Dominican Republic. |