Bodh Gaya is a small town adjacent to the district, located about 101 km to the southeast of Patna , the capital of Bihar . Lord Gautam Buddha attained enlightenment while doing penance under the Bodhi tree in Bodh Gaya . Since then this place is very important for the followers of Buddhism . In the year 2002 , the city was declared a World Heritage Site by UNESCO . Bodh Gayā is a religious site and place of pilgrimage associated with the Mahabodhi Temple Complex in Gaya district in the Indian state of Bihar. It is famous as it is the place where Gautama Buddha is said to have attained Enlightenment (Pali: bodhi) under what became known as the Bodhi Tree.