The structural aesthetics and the interior design of a Dzong (fortress) epitomize the traditional arts and crafts of Bhutan. The exquisite woodwork on the wooden pillars providing structural integrity and the extensive display of murals along the interior walls and a meticulously sculpted statue often gilded in gold sits in the inner sanctum. All fortresses have an extensive collection of sacred text that showcase an amazing art of calligraphy preserved for centuries. The architectural design and its aesthetics of these Fortresses and other religious sites were mostly instructed by Buddhist saints supposedly religion inspired. Subsequent construction by political leaders replicated the essential aesthetics thus preserving the unique features.  Thirteen arts and crafts were recognized and institutionalized. National Institute of Zorig Chusum (13 arts and crafts) offer courses to specialize in these arts and crafts. The institute preserves and promotes these indigenous arts and crafts of Bhutan.