Antonie van Leeuwenhoek was a Dutch fabric salesman who made his own microscopes. They were so powerful he saw things nobody had seen before: a world of microscopic "animalcules" invisible to the naked eye.
Initially nobody believed his reports, but he went on to document many microscopic life forms for the first time in history.
And when people say fracking, what do they mean? Non-conventional gas extraction sometimes involves the use of a "fracturing" process, but not always. So is fracking always a bad thing?
In part 1 of a series, we find out why there is such opposition from the US to fracking, and whether natural gas leaks are a big problem. Next week we will talk about the Australian industry.
Chris Lassig, Stuart Burns, Claire Farrugia and Manisha Bhardwaj.