( ( The ( Magnetic pole ) ) ( ( is ( ( the place ) ( where ( ( ( magnetic ( force lines ) ) ( on ( the earth ) ) ) gather ) ) ) ) . ) )
(ROOT (S (NP (DT The) (JJ Magnetic) (NN pole)) (VP (VBZ is) (NP (NP (DT the) (NN place)) (SBAR (WHADVP (WRB where)) (S (NP (NP (JJ magnetic) (NN force) (NNS lines)) (PP (IN on) (NP (DT the) (NN earth)))) (VP (VBP gather)))))) (. .)))
The Magnetic pole is the place where magnetic force lines on the earth gather.
(ROOT (S (NP (NP (DT The) (NN earth) (POS 's)) (JJ magnetic) (NNS poles)) (VP (VBP have) (VP (VBN switched) (NP (NNS places)) (ADVP (RB repeatedly)) (PP (IN in) (NP (DT the) (NN past))))) (. .)))