公仔箱論壇' o5 U6 p, ?5 |( {3 L2 E# |( J* K, ]
One of Martyn's diving companions, Robbie Schmittner, in a huge flooded cave in Mexico. 公仔箱論壇' Y; R0 S3 |) d/ F+ J
: V$ c/ |" U. z. D' d$ E E9 Q

; x/ H2 F" O, h( e" r4 kDivers 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.公仔箱論壇- E3 k1 [' }& y3 ~
公仔箱論壇 H _. R. W/ y: s5 K2 z- s
2 Y9 `4 c3 `5 P2 [% N. s: @8 K
Divers often use guide-lines to keep them on track in the murky depths. Getting lost can be fatal.
1 e/ \# ?( `) w, Ttvb now,tvbnow,bttvb. `( E6 X. _& C4 \( s* ^
公仔箱論壇% g& r/ D$ w7 d; w6 g
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
3 ]* l" Z m' S+ A
9 L, c3 N4 }& Z2 k% U; Q2 h% F5.39.217.77:8898
L3 n- t; \9 P, u2 A7 b- a公仔箱論壇In another of Martyn's photos Helen Rider swims through the narrow confines of Taina Cave near Santo Domingo in the Dominican Republic. |