Man-Singh-Palace

Chaturbhuj is a Hindu temple excavated in a rock face in the Gwalior Fort, in c875 AD, by Alla, the son of Vaillabhatta, and the grandson of Nagarabhatta of the Gurjara-Pratihara dynasty, in present-day Madhya Pradesh, India.One of the temples inscriptions contains the earliest known inscription of the circular symbol "O", to represent zero, in India, though the Bakhshali manuscript is regarded as the earliest existent use of zero.