天南海北 all corners of the world
Explanation
形容距离遥远，范围极广的不同地区，有时也用来形容说话漫无边际，不着边际。
Describes widely separated and far-reaching regions, sometimes used to describe endless and aimless speech.
Origin Story
话说唐朝时期，一位名叫李白的诗人，为了寻找灵感，他游历了祖国的大江南北，从天寒地冻的北方到艳阳高照的南方，从东海之滨到西域边疆。他走遍了名山大川，欣赏了无数的壮丽景色，体验了各地的风土人情。李白的足迹遍布天南海北，他将自己所见所闻融入诗歌之中，创作出了许多千古传诵的佳作，成为中国历史上伟大的浪漫主义诗人。
It is said that during the Tang Dynasty, a poet named Li Bai traveled throughout China in search of inspiration, from the freezing north to the sunny south, from the East China Sea to the western border. He traveled through famous mountains and rivers, admired countless magnificent landscapes and experienced local customs and traditions. Li Bai's footprints covered the whole country, and he integrated his experiences into his poems, creating many masterpieces that have been passed down through the ages, becoming a great romantic poet in Chinese history.
Usage
用于形容地域范围广阔，也可用以形容谈话内容广泛，不拘一格。
Used to describe the vastness of a region; it can also be used to describe a wide range of conversation topics.
Examples
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张三和李四虽然相隔天南海北，但仍保持着联系。
zhang san he li si suiran xiangge tian nan hai bei,dan reng baochi zhe lianxi
Zhang San and Li Si, although separated by vast distances, still maintain contact.
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他谈起各地风俗习惯，说得天南海北，让人听得入迷。
ta tanqi gedifengsu xiguan,shuode tian nan hai bei,rang ren tingde ru mi
He talked about local customs and traditions, talking about all kinds of topics, which captivated everyone.