Taken from the book Sri Vraj Mandal Parikrama
One day, the supremely playful Sri Krsna was sitting in the shade under the trees on the northen bank of this lake, together with the gopis, and was laughing and joking with vinodini Sri Radhika. At that time, many monkeys from nearby places descended from the trees, being attracted by Krsna's sweet beauty. They respectfully bowed at His lotus feet, sang in joy, jumped and danced. Several monkeys took very long leaps from trees on the sourthern bank of the lake and landed near His lotus feet, and Bhagwan Sri Krsna praised their bravery. Watching this amzaing pastime charmed the gopis. They began to describe the astonishing pastimes of Bhagwan Sri Ramacandra and said that He received help from monkeys. At that time Lalita said," We have heard that in Treta-yuga the greatly powerful Hanuman crossed the ocean in one leap, and today we are seeing with our own eyes monkeys crossing this lake in one single jump."
Hearing this, Krishna proudly declared,"Do you know, I was Sri Rama in Treta-yuga. I performed all these pastimes as Rama."
Lalita praised the amazing pastimes of Sri Ramacandra and then said," You are a liar. You were never Rama. Such bravery is impossible for You."
Sri Krsna smiled and replied,"You do not believe me, but I did take the form of Rama, and I married Sita after breaking the bow of Siva in Janakapuri. On the order of my father, with bow in hand, together with Sita and Laksmana, I roamed through Citrakuta and Dandakaranya where I killed cruel and tyrannical demons. Thereafter, I wandered from forest to forest in seperation from Sita, destroyed Ramana and Lankapuri with the help of monkeys, and then returned to Ayodhya. Now I carry a flute, roam from forest to forest tending and grazing the cows, and perform pastimes with My beloved Sri Radhika in the company of you gopis. Previously, when I came as Rama, My bow and arrow made the three worlds tremble. Now, however, all living beings, both moving and non-moving, are becoming maddened by the sweet sound of my flute."
Smiling, Lalita said,"Mere words will not convince us. If You can show some valour like that of Sri Rama, then we meight believe You. Sri Ramacandra arranged for a bridge to be constructed by bears and monkeys so that He could cross an ocean eight hundred miles wide with His entire army. If You can get these monkeys to construct a bridge over this small lake, then we can believe You."
Hearing Lalita's words, Sri Krsna assembled all the monkeys in a moment by sounding His flute. He ordered them to construct a bridge over the lake using flat stones. On the order of Sri Krsna, thousand of monkeys immediately and eagerly started to help build the bridge, bringing stones from distant places. This occurred right before the gopis eyes. Sri Krsna then constructed the bridge with His own hands with the stones brought by the monkeys. He installed His Ramesvara Mahadeva at the start of the bridge, on the northern side of the lake. These place can be seen to this day. This lake is also called Lanka-kunda.