to feel their presence when you walk and visit them and remember them at greenwood. >> reporter: joe jacobs here every memorial day, but this time he knows little more about his great great grandfather and the others here who fought in the war between the states. arianna howser, cnn, brooklyn, new york. >> and this weekend, of course, americans are remembering our fallen heroes and for thousands of widows across the country, every day is their memorial day. taryn davis lost her husband at 21 and went on to build a sisterhood for those like her and yes that she's this week's cnn hero. >> my husband, corporal michael davis was killed in baghdad, iraq. even four years later people still don't really know how to react when you say, hi, i'm taryn and i am a which hado. after the funeral, i felt ostracized. everybody liked to write off my grief due to my young age. you're young, you'll get repair sgl -- remarried. i come bearing widows. i just wanted to create what i was searching for and just hope there were others there that could come and help me build it, too. i'm taryn davis and invite a new

. >> reporter: this memorial day joe jacobs is honoring a man he never met, his great great grandfather in the civil war. >> he came here from ireland. he we found out he was injured, he was shot. he had a -- that he was a carpenter. >> reporter: jacobs has always known and ogle and his service but he recently learned he has two more relatives who ser served. >> they were actually william ogle's brother in-laws. those we didn't know about. >> reporter: discoveries like those are being repeated over and over again at greenwood cemetery in brooklyn. for the past 10 years, cemetery historician jeff richmond has been trying to figure out exactly how many civil war veterans are here and more about who they are. >> these men sacrificed tremendously, some sacrificing their lives, some losing limbs, some sacrificing their health. and so the least we can do is to honor these men who so faithfully served their country. >> reporter: of the 4600 civil war veterans discovered so far, the majority fought with the union. 76 came from the south. there were 18 generals including two confederate generals