All kinds of yogis—karma, jnana, hatha, etc.—eventually have to attain devotional perfection in bhakti-yoga, or Krsna consciousness, before they can go to Krsna's transcendental abode and never return. Those who attain the highest material planets or the planets of the demigods are again subjected to repeated birth and death. As persons on earth are elevated to higher planets, people in higher planets such as Brahmaloka, Candraloka and Indraloka fall down to earth. The practice of sacrifice called pancagni-vidya, recommended in the Katha Upanisad, enables one to achieve Brahmaloka, but if, in Brahmaloka, one does not cultivate Krsna consciousness, then he must return to earth. Those who progress in Krsna consciousness in the higher planets are gradually elevated to higher and higher planets and at the time of universal devastation are transferred to the eternal spiritual kingdom. When there is devastation of this material universe, Brahma and his devotees, who are constantly engaged in Krsna consciousness, are all transferred to the spiritual universe and to specific spiritual planets according to their desires.