At least five thousand years ago, Srila Sukadeva Gosvami ascertained the existence of Maru in Kalapa-grama and said that Maru, having achieved a yoga-siddha body, would continue to exist until the end of Kali-yuga, which is calculated to continue for 432,000 years. Such is the perfection of mystic power. By controlling the breath, the perfect yogi can continue his life for as long as he likes. Sometimes we hear from the Vedic literature that some personalities from the Vedic age, such as Vyasadeva and Asvatthama, are still living. Here we understand that Maru is also still living. We are sometimes surprised that a mortal body can live for such a long time. The explanation of this longevity is given here by the word yoga-siddha. If one becomes perfect in the practice of yoga, he can live as long as he likes. The demonstration of some trifling yoga-siddha does not constitute perfection. Here is a factual example of perfection: a yoga-siddha can live as long as he likes.