This classic video discusses the rapidly growing field of loop quantum gravity or, more generally, loop cosmology. The main idea behind loop quantum gravity is that space-time is granular and that such granularity is a consequence of quantum mechanics. The powerful implication of this, if, of course, the theory turns our to be correct, is that quantum theory and general relativity can be joined together in what is usually called quantum gravity. Such a powerful junction of the two fields would enable cosmologists to answer some fundamental and almost esoteric questions, for instance, what was the nature of the big bang and what caused it. This video introduces the main ideas of the field and the leading experts, including their interviews.