Ramayana
दुष्करं कृतवान्रामः समुद्रे सेतुबन्धनम् । अश्रुतं पूर्वकैः कैश्चिद्देवैरपि सदानवैः ॥ 7-43-14 ॥
'A hard thing has Rama done — the building of a causeway across the ocean — such as was never heard of before by any of the ancients, nor even by the gods together with the Danavas.
english translation