Kiskindhākānda - Canto 46

While Sugrīva gave instructions to his various generals mentioning in detail the places they were to visit in the course of their expedition in search of Sītā, Śrī Rāma was struck by the knowledge of world geography revealed by Sugrīva and inquired of the latter how he had come to acquire such wonderful and accurate knowledge of geography. In reply to this Sugrīva tells him of the encounter of Vālī with Dundubhi, which led the former to conceive an inveterate hatred towards him (Sugrīva) who when pursued by Vålī had to range from one end of the world to another and this enabled him (Sugrīva) to gather a first-hand knowledge of all parts of the globe.