Large Helical Device
In addition to being the most awesome-looking piece of machinery I have ever seen, the Large Helical Device is billed as the "largest superconducting stellarator in the world". This Japanese fusion research device consists of intertwined coils of superconducting material, and is designed to contain a 100-million-degree nuclear fusion plasma. The research aims to solve the many engineering challenges that must be overcome in order for fusion reactors to produce more energy than they consume.
