Apart from being a shrine to the Lord Buddha, Borobudur is also a temple for Buddhist pilgrimage. A pilgrim’s journey begins at the base of the monument and follows a path around the temple. The pilgrim then ascends to the top of the monument through the three realms in the Buddhist cosmology. Those three realms are Kamadhatu (“the world of desire”), Rupadhatu (“the world of forms”) and Arupadhatu (“the world of formlessness”). However, to experience this journey, the pilgrim will first walk through the gate of the temple adorned with a terrifying head which gives the illusion of the gate looking like the open mouth of the giant. The giant head represents Kala (“time”).

This episode is also available as a blog post: http://martinifisher.com/2021/08/12/batara-kala-and-the-monstrous-faces-of-the-guardians-of-time/