Lord Buddha performed the Twin Miracle (Yamaka Patihara) here.
This mango-tree is located at the gate of Sravasti.
About Gandamba Tree
http://metta.lk/pali-utils/Pali-Proper-Names/gandamba.htm
About Twin Miracle (Yamaka Patihara)
http://en.wikipedia.org/wiki/Miracles_of_Buddha#Twin_Miracle
http://www.palikanon.com/english/pali_names/y/yamaka_paatihaariya.htm