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great depth; bottomless
great height
登山家は、千尋の谷を覗き込んだ。
The mountaineer peered into the bottomless valley.
千尋の海底に竜が棲む。
A dragon dwells in the fathomless depths of the sea.
彼の悲しみは、千尋の淵のようだ。
His sorrow is like a bottomless abyss.