Destruction is multi-faceted. Even the simplest system has a structure and performs functions. If the spatial continuity or arrangement of an entity's structure is severed or substantially transformed - its functions are usually adversely affected. Direct interference with a system's functionality is equally deleterious. We can render a system dysfunctional by inhibiting or reversing any stage in the complex processes involved - or by preventing the entity's communication with its environs. Another method of annihilation involves the alteration of the entity's context - its surroundings, its codes and signals, its interactive patterns, its potential partners, friends and foes. Finding the lethal weaknesses of an organism, an apparatus, or a society is described as a process of trial and error. But the outcome is guaranteed: mortal susceptibility is assumed to be a universal trait. No one and nothing is perfectly immune, utterly invulnerable, or beyond extermination. Yet, what is poison to one species is nectar to another. Water can be either toxic or indispensable, depending on the animal, the automaton, or the system. Scorching temperatures, sulfur emissions, ammonia or absolute lack of oxygen are, to some organisms, the characteristics of inviting habitats. To others, the very same are deadly. Can we conceive of an indestructible thing - be it unicellular or multicellular, alive or robotic, composed of independent individuals or acting in perfect, centrally-dictated unison? Can anything be, in principle, eternal? This question is not as outlandish as it sounds. By fighting disease and trying to postpone death, for instance, we aspire to immortality and imperishability. Some of us believe in God - an entity securely beyond ruin. Intuitively, we consider the Universe - if not time and space - to be everlasting, though constantly metamorphosing. What is common to these examples of infinite resilience is their unbounded and unparalleled size and might. Lesser objects are born or created. Since there has been a time, prior to their genesis, in which they did not exist - it is easy to imagine a future without them. Even where the distinction between individual and collective is spurious their end is plausible. True, though we can obliterate numerous "individual" bacteria - others, genetically identical, will always survive our onslaught. Yet, should the entire Earth vanish - so would these organisms. The extinction of all bacteria, though predicated on an unlikely event, is still thinkable. But what about an entity that is "pure energy", a matrix of fields, a thought, immaterial yet very real, omnipresent and present nowhere? Such a being comes perilously close to the divine. For if it is confined to certain space - however immense - it is perishable together with that space. If it is not - then it is God, as perceived by its believers.