A lotus pond near Rājagaha. The Saṃyutta Nikāya mentions the Buddha as relating the story of a man who went to Sumāgadhā with the thought, “I will speculate about the world.” He saw an army, with its four divisions, enter a lotus stalk. He then thought he must be mad and told everyone so. The Buddha explained that what the man had seen was real; it was an Asura army, fleeing from the devas in panic, through a lotus stalk. SN.v.447f.
Near the pond was the Moranivāpa, and within walking distance was the Paribbājakārāma in Queen Udumbarika’s park. The Buddha was walking about in the open air near Sumāgadhā, just before he preached the Udumbarikasīhanāda Sutta. DN.iii.40