what is the largest city in africa that is on the banks of the nile river?
return africa ;return cities of #1 ;return the  nile river ;return banks of #3 ;return #2 on #4 ;return size of #5 ;return #5 where  #6 is highest
['select', 'project', 'select', 'project', 'filter', 'project', 'superlative']