Mahamaya: Every night there was a program at the pandal, and once, when Prabhupada had asked for questions at the end of his lecture, a challenging man came up to the microphone and said, “Can you show me a miracle?” We thought he was demanding that Prabhupada produce ashes in his hands like Sai Baba and others. Prabhupada looked at the 150 devotees sitting on the stage in front of him, swooped his hand to indicate us and said, “This is my miracle. I have changed these mlecchas and yavanas into Vaishnavas.” We all cheered, “Haribol! Jaya!” We were so happy to be his examples of success.
Reference: Remembrances by Sidhanta Das- Folio Vedabase