<prompt> Translate the following text to EnglishMnara wa nguzo nane uliojengwa kwa ukumbi wa kifalme wa Humayun baada ya kushindwa na jeshi la China mnamo 1540.  <response>: With a proud octagonal tower that rises out of the top of the structure, it was built to mark the passage of the Emperor Humayun after his defeat in the 1540s. 