South Africa's Mandela still 'critical but stable' JOHANNESBURG (Reuters) - Ailing anti-apartheid leader and former South African President Nelson Mandela remained in hospital on Monday in a "critical but stable" condition, the government said. Mandela has been in a Pretoria hospital for more than three weeks receiving treatment for a recurring lung infection, his fourth hospitalization in six months. The faltering health of the 94-year-old, a figure admired globally as a symbol of struggle against injustice and racism, has reinforced a realization that the father of the post-apartheid South Africa will not be around forever. While he lies in hospital, many South Africans are looking ahead to his 95th birthday on July 18. "We must all be able to do something good for humanity on this day in tribute to our former President," President Jacob Zuma said in a statement. Mandela's health also dominated a two-day visit to South Africa by U.S. President Barack Obama over the weekend. Obama met the Mandela family on Saturday, offering words of comfort and praising the retired statesman as one of history's greatest figures. Reporting by Olivia Kumwenda; Editing by Ed Cropley