Somapura Mahavihara in Paharpur, Badalgachhi Upazila, Naogaon District, Bangladesh is among the best known Buddhist viharas in the Indian Subcontinent and is one of the most important archeological sites in the country. It was designated a UNESCO World Heritage Site in 1985.
A number of monasteries grew up during the Pāla period in ancient Bengal and Magadha. According to Tibetan sources, five great Mahaviharas stood out: Vikramashila, the premier university of the era; Nalanda, past its prime but still illustrious, Somapura Mahavihara, Odantapurā, and Jaggadala. The five monasteries formed a network; "all of them were under state supervision" and there existed "a system of co-ordination among them. It seems from the evidence that the different seats of Buddhist learning that functioned in eastern India under the Pāla were regarded together as forming a network, an interlinked group of institutions," and it was common for great scholars to move easily from position to position among them.
The excavation at Paharpur, and the finding of seals bearing the inscription Shri-Somapure-Shri-Dharmapaladeva-Mahavihariyarya-bhiksu-sangghasya, has identified the Somapura Mahavihara as built by the second Pala king Dharmapala (circa 781-821) of Pāla Dynasty. Some clay seals from the ruins bear the inscription Shri-Somapure-Shri-Dharmapaladeva-Mahavihariyarya-bhiksu-sangghasya. Tibetan sources, including Tibetan translations of Dharmakayavidhi and Madhyamaka Ratnapradipa, Taranatha's history and Pag-Sam-Jon-Zang, mention that Dharmapala's successor Devapala (circa 810—850) built it after his conquest of Varendra.
The quadrangular structure consists of 177 cells and a traditional Buddhist stupa in the center. The rooms were used by the monks for accommodation and meditation. In addition to the large number of stupas and shrines of various sizes and shapes, terracotta plaques, stone sculptures, inscriptions, coins, ceramics etc. have been discovered. The site houses the architectural remains of a vast Buddhist monastery, Somapura Mahavihara, covering 27 acres (110,000 m2).
It was an important intellectual centre for Dharmic Traditions such as Buddhists (Buddha Dharma), Jains (Jaina Dharma) and Hindus (Sanatana Dharma) alike. The 21 acre (85,000 m²) complex has 177 cells, viharas, numerous stupas, temples and a number of other ancillary buildings. The outside walls with ornamental terracotta palques still display the influence of these three religions.
The purpose of this central structure at the midst of the courtyard remains unsolved since its discovery. Hence most of the debates generated hitherto on the architecture of Sompur Mahavihara are cantered on the identification its missing superstructure. The reason may be manifold, but the most important one is the non-availability of substantial amount of first hand resource including a comprehensive architectural documentation at the disposal of the researchers. There are different arguments regarding the terminating top of the central structure of Sompur Mahavihara.
Somapura was designated a UNESCO World Heritage Site in 1985. Since then, a series of UNESCO missions has regularly visited the site and helped with the project. Moreover, the UN body also prepared a master plan, involving 5.6 million dollars. The various terracotta artworks within the site have suffered from serious damage as a result of "lack of proper maintenance, shortage of manpower, fund constraint and heavy rainfall." Furthermore, poor water drainage in the site accompanied by high levels of salinity in the soils has also contributed to decay the terracotta sculptures. Other threats include uncontrolled vegetation, vandalism, climatic conditions, and public trespassing and encroachment.
Sompur Bihar at Paharpur is about 282 ;km by road from Dhaka and it will take about 6.5 hours to reach Paharpur by bus/taxi/private car if no major stops are made along the way. If one starts from Dhaka, the route shall be Dhaka - Savar - Chandra - Tangail - Jamuna Bridge - Naogaon - Badalgachhi - Paharpur. The best way to tour the site is to first reach Naogaon and stay there in hotel or reach Badalgacchi and stay there in Dakbanglo.