recommended as an engrossing story about a horrifying historical event and the elements which contributed to it . 
(ROOT (S (VP (VBN recommended) (PP (IN as) (NP (NP (DT an) (JJ engrossing) (NN story)) (PP (IN about) (NP (NP (DT a) (JJ horrifying) (JJ historical) (NN event)) (CC and) (NP (NP (DT the) (NNS elements)) (SBAR (WHNP (WDT which)) (S (VP (VBD contributed) (PP (IN to) (NP (PRP it)))))))))))) (. .)))
(ROOT (S (VP (VBN ) (PP (IN ) (NP (NP (DT ) (JJ ) (NN )) (PP (IN ) (NP (NP (DT ) (JJ ) (JJ ) (NN )) (CC ) (NP (NP (DT ) (NNS )) (SBAR (WHNP (WDT )) (S (VP (VBD ) (PP (IN ) (NP (PRP )))))))))))) (. )))