Valmiki Ramayana Yuddha Kanda Sarga 41 Shloka 32

रामवाक्यप्रचोदिताः commanded by Rama's words, वनौकसः gardens, पताकामालिनीम् decorated with flags, रम्याम् beautiful to look at, उद्यानवनशोभिताम् embellished with gardens, चित्रवस्राम् wonderful, सुदुष्प्रापाम् defensive walls, उच्चैः tall प्राकारतोरणाम् archways of boundary, सुरैरपि even for Devatas, दुर्धर्षाम् difficult to access, ताम् they, यथानिदेशम् as ordained, सम्पीड्य remaining, न्यविशन्त entered.

Commanded by Rama's words the Vanaras remaining in their positions as ordained, entered the wonderful Lanka, which was decorated with flags, embellished with gardens. The defensive walls and arches of the boundary of Lanka were difficult to access even for Devatas.