Despite a variety of medium and scale employed by Hirst, his works are tied through the common themes of death, life, religion, beauty and science. Through the seemingly morbid fascination with life and death, predominant in his work, Hirst challenges contemporary belief systems and tensions that may arise when death is discussed and portrayed through art. The skulls reference mortality, which is juxtaposed against the spiritual symbolism of the butterfly that is depicted in Hirst's works as embodiments of the beauty of life and their impermanent existence. The symbolism of the skull, however, is one that is also presented as a celebration of life; a nod to Mexican and European traditions and is often produced in a variety of bright tones and iridescent foiling.