Why some countries are poor and others rich?

why some countries are very rich that they can even build anything they want easily without difficulties whether its spaceship or huge Aircraft carrier , or big new cities , or multi billion dollar companies and others are very poor that they cant even build 1km road for their people , please explain this to... show more why some countries are very rich that they can even build anything they want easily without difficulties whether its spaceship or huge Aircraft carrier , or big new cities , or multi billion dollar companies and others are very poor that they cant even build 1km road for their people ,

please explain this to me very well ,

and if we look back the old days of the most richest countries on earth , we can see that they were also very poor in the past like 200 years ago and even some rich countries were very poor around 60 years ago but right now are very rich

and some countries were very poor countries around 200 years ago and still are very poor , why they are not developing, what is holding them back ,
thank you very much
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