The thangka that you see on this page is of the Kalachakra mandala. The majestic palace that you see on this page is a symbolic entity, a visualisation aid. It has four gates, each oriented to the four quarters of the world, and is protected by blue, scarlet, and gold discoids, each standing for a spiritual ideal that one must attain in order to access the riches offered by the Kalachakra palace. Zoom in on the splendour of the sprawling gates of the palace - note the perfect symmetry and attention to detail with which the same have been painted.
The importance of mandalas in Vajrayana Buddhism is in the fact that they are visualisation aids. Each of the five stories of the Kalachakra mandala palace leads the practitioner through the realms of body, expression, intellect, consciousness, and bliss to the resident Kalachakra deity. Practice empowers one to visualise and penetrate each and every corner of this all-important structure.