Valmiki Ramayana Yuddha Kanda Sarga 3 Shloka 15
Original Shlokaसर्वतश्चमहाभीमाश्शीततोयवहाश्शुभाः । अगाधाग्राहवत्यश्चपरिखामीनसेविता ।।6.3.15।।
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सर्वताः all round it, महाभीमाः very frightening, शीततोयाः very cold water, महाशुभाः very splendid, अगाधाः fathomless, ग्राहवत्यश्च: crocodiles, मीनसेविताः inhabited by fish, परिखा: moats
All round it (boundary wall) are very splendid moats filled with frighteningcold water inhabited by fish and crocodiles.