Thanks PGC!! It was a great session.
I was looking for some info on globulars when I came across this site:
http://www.forum.seds.org/messier/more/sagdeg.html
It describes how the globular M54 is thought to be part of the remnants of a dwarf galaxy that the milky way has absorbed and that NGC 5139 Omega Cen is also thought to be the remnants of a dwarf galaxy core. There is more to some of these objects than I thought.