Soweto , South Africa ( CNN ) -- There are still bullet holes in the stained-glass windows of this church . They 're a reminder , Tommy Zwane says , of the dark days before Nelson Mandela became his country 's first democratically elected president . The Regina Mundi Catholic Church in Soweto was at the heart of the uprising against apartheid -- most famously on June 16 , 1976 , when young students rebelled against the education system and were fired upon by police . `` Things were difficult for everybody , for black people in this country . We used to run and come to this church to pray to God so that he could come and assist us , because we were in trouble at that time , '' Zwane said . `` There was no understanding between us and the government of South Africa . '' On Sunday , people filled the church 's pews for a very different reason -- to sing , pray and honor Mandela 's legacy days after his death in a home nearby . Services at churches , synagogues and mosques throughout South Africa honored Mandela . The national day of remembrance is one of a string of events planned to say farewell to the iconic figure who helped South Africa break the practice of racial segregation and end white minority rule . A massive memorial service is scheduled for Tuesday in Johannesburg 's FNB Stadium , which can hold 94,000 people . A state funeral will be held December 15 in Mandela 's ancestral hometown of Qunu in the Eastern Cape province . At least 70 heads of state and 10 former heads of state have said they 're coming to South Africa this week , government international relations spokesman Clayson Monyela said . From the United States , officials said , U.S. President Barack Obama and first lady Michelle Obama will be accompanied by President Jimmy Carter , President George W. Bush and President Bill Clinton and their wives . More than two dozen U.S. lawmakers are also scheduled to attend . South African President Jacob Zuma , who announced Mandela 's death Thursday , used the revered leader 's well-known clan name Sunday as he asked churchgoers to remember the former president 's values . `` When I say we pray for the nation , ( it ) is that we should pray for us not to forget some of the values that Madiba stood for , that he fought for , that he sacrificed his life for , '' he said . `` He stood for freedom . He fought against those who oppressed others . He wanted everyone to be free . '' In a suburb of Pretoria , parishioners said they were grateful for the man who saved them from revenge . `` His presence in our lives meant so much for the Afrikaaner people , allowed them to get rid of their guilt feelings and to participate in the journey that he invited us to join , '' Wilhelm Jordaan said . In Soweto , Kathy and Stewart Allen said they do n't normally attend the Regina Mundi church . But they wanted to be there on Sunday . `` We believe that this church embodies all the history , and everything that he stood for , '' Kathy Allen said . Once again , Stewart Allen said , Mandela has brought the country together . CNN 's Kim Norgaard and Catherine E. Shoichet contributed to this report from Atlanta .
NEW : Official : 70 heads of state are coming to South Africa to honor Nelson Mandela . Churchgoers in Soweto celebrate Nelson Mandela 's legacy . Services are held nationwide on a day of remembrance for Mandela . A state funeral will be held December 15 .