an engrossing story about a horrifying historical event 
(ROOT (NP (NP (DT an) (JJ engrossing) (NN story)) (PP (IN about) (NP (DT a) (JJ horrifying) (JJ historical) (NN event)))))
(ROOT (NP (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (DT ) (JJ ) (JJ ) (NN )))))