Massive stars play a hugely important role in the evolution of the Universe. These objects, more than 10 times the mass of our Sun and up to 1 million times brighter, transformed the chemical make up of the Universe by processing hydrogen in their cores and releasing heavy elements upon their explosive deaths. But do all massive stars end their lives this way? Here, I will discuss the lives and deaths of these cosmic engines, as well as their broader importance in the Universe we inhabit.