What we don't know about the world - BBC Medical tests at the top of the world Laying cable for deep sea research Africa and Europe set for tunnel link Viking ship sets sail for Dublin Scott v Shackleton: One died, one survived. So who is the more worthy hero?

UK polar team set to make history - Jan 2007 UK team makes polar trek history - Jan 2007

4300km Arctic trek to map climate impacts - Feb 2007

NASA mission explore's world's deepest sinkhole in Mexico World's longest underground river discovered in Mexico by divers

Science team finds 'lost world', Papua, Indonesia Biking through Cambodia's jungle

Amazon River 'longer than Nile' Explorer blazes trails through Venezuela's 'Lost World'