sa nirmaya puras tisro
tabhis te ’sura-senanyo
lokams trin sesvaran nrpa
smaranto nasayam cakruh
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Maya Danava, the great leader of the demons, prepared three invisible residences and gave them to the demons. These dwellings resembled airplanes made of gold, silver and iron, and they contained uncommon paraphernalia. My dear King Yudhisthira, because of these three dwellings the commanders of the demons remained invisible to the demigods. Taking advantage of this opportunity, the demons, remembering their former enmity, began to vanquish the three worlds — the upper, middle and lower planetary systems.