Through out the whole song it goes, Em, C, D, G. These 4 chords get repeated 
through out the song. Standard tuning: E,B,D, G, A, E. 
For example:

Em (022000@1)                 CThere's (x32010@1)a place we know,
D (xx0232@1)                        GWhat's (320003@1)cold enough won't grow
Em (022000@1)              CWe (x32010@1)have seen the dark
 D (xx0232@1)                        Gand (320003@1)the darkness took its toll



This pattern continues throughout the whole song.

The strumming pattern is: D-U-U-D-U-U-D-U-U-D
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