For Buddhists, the universe has no beginning. Various world systems come into existence and eventually cease to be, but other worlds precede and follow them. The Buddha is said to have discouraged speculation about the origin of the universe; the question of whether the world has a beginning is one of fourteen questions that the Buddha refused to answer. He also remained silent when asked whether the universe will ever come to an end. Individual worlds are destroyed, incinerated by the fire of seven suns; but, no apocalypse, no final end time, is foretold. Individual beings put an end to their individual existence, one that also has no beginning, by traversing the path to nirvana.