Nandana was a fort in eastern flanks of Salt Range in Punjab Pakistan. It was ruled by Hindu Shahi family and Mahmud of Ghazni expelled them from here. It was built on a hilly range and it ruins are present.
Anandapala the son of Jayapala of the Hindu Shahi dynasty had erected the Shiva temple in Nandan  Nandana also means 'Son' in Sanskrit. Nandana is the name of the garden owned by hindu Dev chief 'Indra'.
Nandana & The greatest Persian scholar Abū Rayḥān al-Bīrūnī
The greatest Persian scholar Abū Rayḥān al-Bīrūnī calculated the circumference of earth here 1000 years ago. He found the Potohar Plateau so flat that he could see the curvature of earth and decided this would be the ideal place to calculate the circumference of earth.His calculation is only 80miles short of modern day digital precision tools calculation and how he did it a millennium ago is mind boggling
- ^ Pakistan journal of history and culture, Volume 17 By National Institute of Historical and Cultural Research (Pakistan)Page 122
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