The revolution in 20th-century physics has changed the way we think about space, time and matter and our own place in the universe. It has suggested answers to many of the big questions of existence, such as the ultimate nature of things and the how the universe came into being. It has undermined our belief in a Newtonian mechanistic universe and a deterministic future, posing questions about parallel universes, time-travel and the origin and end of everything. At the same time, we have witnessed amazing attempts at unification so that physicists are able to contemplate the discovery of a...