Adhai din ka Jhonpra at Ajmer is the architectural work that was formerly a monastery.

Explanation:

- Adhai din ka Jhonpra is a mosque located in Ajmer, Rajasthan, India. It is one of the oldest mosques in India and holds historical significance.
- The name "Adhai din ka Jhonpra" translates to "shed of two and a half days" in English. This name is derived from the legend that the mosque was constructed in just two and a half days.
- The mosque was originally a Sanskrit college and a Hindu temple dedicated to Lord Vishnu. It was believed to have been built in the 12th century during the reign of Prithviraj Chauhan.
- However, in the year 1198, the mosque was destroyed by Mohammad Ghori, a Turkish ruler. The mosque was then rebuilt using the remnants of the Hindu temple.
- The architecture of Adhai din ka Jhonpra reflects a blend of Hindu and Islamic styles. The entrance of the mosque is adorned with intricate carvings and Quranic inscriptions.
- The main prayer hall of the mosque is supported by a series of pillars with beautiful arches. The walls of the mosque feature delicate screens with geometric patterns.
- The mihrab, which indicates the direction of Mecca, is placed in the central part of the mosque. It is decorated with intricate carvings and inscriptions.
- Adhai din ka Jhonpra is known for its unique architectural style and historical significance. It attracts visitors from all over the world who are interested in exploring the rich history and cultural heritage of India.
- Today, the mosque is a protected monument under the Archaeological Survey of India and is open for visitors to explore and appreciate its architectural beauty.

In conclusion, Adhai din ka Jhonpra at Ajmer was originally a monastery but was later transformed into a mosque with a unique blend of Hindu and Islamic architectural styles.