Sri Sri Radha-Krishna become Ganga


"Once, on the full moon of Karttika, a festival honoring Srimati Radharani was being nicely celebrated. Shri Krishna was worshiping Radharani in His rasa-mandala in Goloka, when many other exalted personalities, including the four Kumaras, demigods, demigodesses, sages, saints and others arrived to also worship the beloved of Lord Krishna. They presented her various precious gifts. Lord Shiva began singing songs like nectar for the pleasure of Lord Krishna. All the demigods fell unconscious. Upon regaining their consciousness, they saw that the entire rasa-mandala was flooded with water
and Sri Sri Radha-Krishna had disappeared. Lord Brahma understood that the divine couple had transformed Themselves into that water, which became known as Ganga. This water is the bestower of pure bhakti, which is why the entire universe worships Ganga." (Brahma-vaivarta Purana, Prakriti Khanda 9, Narayana Rishi replies to Narada)