Lingaraj Temple is a Hindu temple dedicated to Harihara, a form of Shiva and is one of the oldest temples of Bhubaneswar, the capital of the East Indian state of Odisha. The temple is the most prominent landmark of the Bhubaneswar city and one of the major tourist attractions of the state
The Lingaraja temple is the largest temple in Bhubaneswar. The central tower of the temple is 180 ft (55 m) tall. The temple represents the quintessence of the Kalinga Architecture and culminating the medieval stages of the architectural tradition at Bhubaneswar.The temple is believed to be built by the kings from the Somavamsi dynasty, with later additions from the Ganga rulers. The temple is built in the Deula style that has four components namely, vimana (structure containing the sanctum), jagamohana (assembly hall), natamandira (festival hall) and bhoga-mandapa (hall of offerings), each increasing in the height to its predecessor. The temple complex has 50 other shrines and is enclosed by a large compound wall.
Bhubaneswar is called the Ekamra Kshetra as the deity of Lingaraj was originally under a mango tree (Ekamra) as noted in Ekamra Purana, a 13th-century Sanskrit treatise. The temple is active in worship practises, unlike most other temples in Bhubaneswar and Shiva is worshipped as Harihara, a combined form of Vishnu and Shiva. The temple has images of Vishnu, possibly because of the rising prominence of Jagannath cult emnating from the Ganga rulers who built the Jagannath Temple in Puri in the 12th century.
Lingaraj means “The king of Lingam”, the symbol of Saivism. Shiva was worshipped as Kirtivasa and later as Harihara and is commonly referred as Tribhuvaneshwara (also called Bhubaneswar), the master of three worlds, namely, heaven, earth and netherworld). His consort is called Bhuvaneshvari.
The temple is more than 1100 years old, dating back in its present form to the last decade of the eleventh century, though there is evidence that part of the temple was built during the sixth century CE as the temple has been emphasized in some of the seventh century Sanskrit texts. Fergusson believes the temple might have been initiated by Lelat Indra Kesari who reigned from 615 to 657 CE. The Assembly hall (jagamohana), sanctum and temple tower wer built during the eleventh century, while the Hall of offering (bhoga-mandapa) was built during the twelfth century. The natamandira was built by the wife of Salini between 1099 and 1104 CE.By the time the Lingaraj temple was completely constructed, the Jagannath (form of Vishnu) cult had been growing in the region, which historians believe is evidenced by the co-existence of Vishnu and Shiva worship at the temple. The Ganga dynasty kings were ardent followers of Vaishnavism and built the Jagannath Temple at Puri in the 12th century. You can find more Here.