Anuradhapura is one of the most important religious cities in Sri Lanka. The Bodhi tree is a cutting from the tree that Buddha is said to have attained enlightenment under. It also has the two largest Stupa's in Sri Lanka.
The best way to explore Anuradhapura is with a guide as its more about the history than visually stunning places.
We used Navin who was absolutely amazing, you can contact him at his website: https://navinlankatours.com/