Sentence:  The long reaches that were like one and the same reach, monotonous bends that were exactly alike, slipped past the steamer with their multitude of <WSD>secular</WSD> trees looking patiently after this grimy fragment of another world, the forerunner of change, of conquest, of trade, of massacres, of blessings. 
Meaning of the word marked with <WSD> tags:  Centuries-old, ancient.