A hidden gem in Boston's Mary Baker Eddy Library (next to the Christian Science Center on Mass Ave) the Mapparium holds within it a three story stained glass globe - it's breathtaking. Pictures aren't allowed, but the inside and outside of the building is just as pretty.
from their website
My advice? Go on one of the free admission days, not so you don't have to pay (normally it's $5--not exactly breaking the bank). But go because on these days, you can stare on the inside of this marvelous globe as long as you want, with no awkward voice-over movie thing to diminish the pure awe you feel inside of the world.