Located in Anuradhapura, this tank is known as the first irrigational tank that was built in ancient Sri Lanka. Records say that it was Prince Anuradha who built this tank first. Prince Anuradha ruled Anuradhapura, giving his name as a namesake for the city. Later King Pandukabhaya enlarged the clear lake further and named it Abhayavapi, giving it the name of one of his uncles who reigned before him. As time passed, the name of the lake changed from its original name to Basawakkulama, but sometimes people still refer to it as Abhaya Wewa. When full, the Basawakkulama Wewa spans for 330 acres. Just like in the ancient times, the lake still functions perfectly, and is used to provide water for the neighboring people.