And, O chief of the Bharatas, having by my own prowess crossed the ocean, that abode of sharks and crocodiles, I saw in Ravana’s residence, the daughter of king Janaka, Sita, like unto the daughter of a celestial. And having interviewed that lady, Vaidehi, Rama’s beloved, and burnt the whole of Lanka with its towers and ramparts and gates, and proclaimed my name there, I returned.

In plain words: Hanuman tells Bhima how he crossed the ocean by his own strength and found Sita, King Janaka's daughter, in the palace of Ravana, the demon king. After meeting her, he set fire to Lanka, Ravana's city, announced his name there, and came back.