yad ādhayo vyādhayaś ca
klamas tandrā parābhavaḥ
Viśvakarmā is the engineer or architect for the palatial buildings in the heavenly planets. Therefore, since he was engaged to construct the residential quarters of Bali Mahārāja, the buildings and palaces on the planet Sutala must at least equal those on the heavenly planets. A further advantage of this place designed for Bali Mahārāja was that he would not be disturbed by any outward calamity. Moreover, he would not be disturbed by mental or bodily miseries. These are all extraordinary features of the planet Sutala, where Bali Mahārāja would live.
In the Vedic literatures we find descriptions of many different planets where there are many, many palaces, hundreds and thousands of times better than those of which we have experience on this planet earth. When we speak of palaces, this naturally includes the idea of great cities and towns. Unfortunately, when modern scientists try to explore other planets they see nothing but rocks and sand. Of course, they may go on their frivolous excursions, but the students of the Vedic literature will never believe them or give them any credit for exploring other planets.