A mega effort is on in southern France where countries that represent half the world's population are together collaborating to create a 'miniature Sun' on Earth in an effort to harness the benefits of fusion power. In this process, two heavier atoms of Hydrogen are fused together to produce unlimited quantities of energy from a relatively non-polluting source. Dr Mark Henderson, a scientist at the ITER project The Path (earlier called the International Thermonuclear Experimental Reactor project), explains why the place he stands is unique since it will house the coldest place in the Universe and also within a few metres it will house the reactor that mimics the Sun creating temperatures of about 150 million degrees Celsius. It is this huge temperature gradient and how to manage it is what is the biggest challenge for the global scientific community. At Euro 20 billion, the ITER project is the most expensive scientific project on Earth.