Anne Boleyn's Pickled Heart

My sister has an encyclopedia of useless information, and this was under "Anne Boleyn":

"After Anne Boleyn was executed in 1536, her heart was stolen. It was discovered exactly three hundred years later, buried under a church organ in Suffolk."

Well that's a little freaky! How did they know it was hers? After three hundred years, how did they even know it was a heart? And how come we never learn cool stuff like this in History class?

I wonder what other bits and pieces of poor Anne are out there.