Drat, you have to be under 25. Anyway, I'd rather do it by boat
But a nice question. When I was in my 20s I would have come up with a lot of 'must do's but I now wonder whether it's all worth the effort when you can see so much on TV and the internet?
Anyway, off the top of my head, the Amazon and the Andes would be a priority - so a trek across South America. Need to think more ... but then I'm still thinking about my ten best places in Europe .... the World? Give me a year or two ...
