Yuddhakānda - Canto 37

While, on reaching the precincts of Lankā, Śrī Rāma and Sugrīva as well as other monkeys headed by Hanumån were deliberating as to how to achieve success in their expedition, Vibhīsana apprises them of the arrangements made by Rāvana at the four gates for the defence of Lankā, as reported to him by his four ministers, who had entered Lankā in the disguise of birds and witnessed everything with their own eyes. Śrī Rāma too after detailing monkeys to storm the four gates climbs up the Suvela mountain with his army.