Descent of the Ganges, known locally as Arjuna's Penance, is a monument at Mamallapuram, on the Coromandel Coast of the Bay of Bengal, in the Chengalpattu district of the state of Tamil Nadu, India. Measuring 96 by 43 feet (29 m × 13 m), it is a giant open-air rock relief carved on two monolithic rock boulders.