1. The Old Faithful geyser in the Yellowstone National Park in the USA shoots boiling water into the air every hour. :eek:
2. Our muscles only work in one way, by pulling. They never push. :cool:
3. A man weighing 68 kg would require a breastbone 2 metres long to hold all the muscles for powering a pair of wings that could lift him off the ground. :eek:

