an exhilarating place to visit , this laboratory of laughter 
(ROOT (NP (NP (NP (DT an) (JJ exhilarating) (NN place)) (SBAR (S (VP (TO to) (VP (VB visit)))))) (, ,) (NP (NP (DT this) (NN laboratory)) (PP (IN of) (NP (NN laughter))))))
(ROOT (NP (NP (NP (DT ) (JJ ) (NN )) (SBAR (S (VP (TO ) (VP (VB )))))) (, ) (NP (NP (DT ) (NN )) (PP (IN ) (NP (NN ))))))