This is another soundtrack from Pirates of the Caribbean At world's End, composed by Hans Zimmer
Listen to the track to get a feel of it.
The first minute(out of two) is just a simple melody in the Am scale.
There are other instruments playing what sounds to me like B and D notes to give a pinch 
variation and to sort of "make it" an Amsus2/Amsus4.

This is the intro (Also played on the Am chord with the solo):
E --------------------------------|
B 1-0-1---0-1---0-1-0-1---0-1---0-|
G ------2-----2---------2-----2---|
D --------------------------------|
A --------------------------------|
E --------------------------------|

Solo, with chords on top:

   Am          G    Em        Am    Am         G         Dm       E       Am
E----------------------------------------------------------------------------|
B----------------------------------------------------------------------------|
G-5---------------------------------5----------------------------------------|
D---7-----------5---5-----------------7-----------5--------------------------|
A-----7---5---5-------7-----------------7---5---5------8-7-8-----5-7---------|
E-----------8-----------7---5-7-8-------------8----------------8-------8-7-5-|


The melody that plays during the whole track changes when the Chords change (makes sense!)

For G and Em:
E---------------------------------|
B--0---0-----0-----0--0-----0-----|
G----2---0-2---0-2--2---0-2---0-2-|
D---------------------------------|
A---------------------------------|
E---------------------------------|

For the Dm chord:
E--0-1---0-1---0-1-0-1---0-1---0-1-|
B------3-----3---------3-----3-----|
G----------------------------------|
D----------------------------------|
A----------------------------------|
E----------------------------------|

For the Finish (E and Am)
E------------------|
B--5-4-5---5-4-5---|
G--------4-------4-|
D------------------|
A------------------|
E------------------|