"Men wanted:
for hazardous journey. Low wages,
bitter cold, long hours of complete darkness.
Safe return doubtful. Honour and recognition
in event of success "
- Sir Ernest H. Shackleton


Those enthused by the above should check
the following one out:
http://blog.ted.com/2007/06/to_the_depths_o_1.php

It is a presentation by Bill Stone at TED (cave explorer
and diver -- who has invented robots and breathing
equipment to let him plumb Earth’s deepest abysses)