Islamic Calligraphy done on one of the walls inside the Mosque
Arabic: 'Laa ilaaha illalaah, Mohamed ar-Rasool Allah'
English translation: ‘There is absolutely no deity worthy of worship except Allah, and Mohamed (saws) is the Messenger of Allah.’
Also the names of the companions of the Holy Propher (P.B.U.H) have been engraved

Classic Mughal Calligraphy by Yawar Masood, on Flickr