JOHANNESBURG -- Two by two, the children marched into the assembly hall at Piet van Vuuren Primary School in the working class neighborhood of Brixton, their white, black and brown faces a tribute to the man they had come to praise.
"Happy Birthday, Tata Madiba," they pealed, hundreds of voices in cacophonous unison, using the clan name for Nelson Mandela, South Africa's ailing first black president. "We love you, we do!"
Before 1994, when Mr. Mandela was elected president, this school was reserved for white children under the harsh system of segregation known as apartheid. Now, the school is the very picture of the Rainbow Nation that Mr. Mandela strove to create.
"If it wasn't for Tata Madiba, I wouldn't be in this school right now," said Luzuho Mdizu, 12, a seventh grader who is the school's top male student. "He is my hero."
Across the country on Thursday, South Africans spent 67 minutes on Mr. Mandela's 95th birthday helping others as a tribute to Mr. Mandela's 67 years in public service.
After weeks battling critical illness, Mr. Mandela remained in the hospital on Thursday although the authorities said his condition was "steadily improving."
The upbeat assessment contrasted with the widespread concern among South Africans and those around the world that Mr. Mandela might not recover from a lung infection that forced him into the hospital on June 8 for the fourth time in a year. Previously, the authorities had described his condition as critical but stable.
In a statement released on Thursday, President Jacob Zuma wished Mr. Mandela a happy birthday and said, "Madiba remains in hospital in Pretoria but his doctors have confirmed that his health is steadily improving."
In an interview with Britain's Sky News, one of Mr. Mandela's daughters, Zindzi Mandela-Motlhajwa, said on Wednesday that Mr. Mandela was watching television and using headphones to hear the sound.
"You can see he is there in his eyes, the same energy and strength," she said. The family planned to present Mr. Mandela with a collage of family photographs as a birthday gift, she said.
Little is known about the details of his medical condition. A court affidavit filed in June in a dispute within Mr. Mandela's family over where he might be buried claimed he was in a permanent vegetative state, but both family and medical team members have since denied this. Family members and friends who have visited him more recently say that Mr. Mandela is sometimes awake, smiling, communicating with his eyes and even trying to talk.
On Thursday, hundreds of people gathered outside the Pretoria hospital where Mr. Mandela has been treated for the past 40 days. Officials from the African National Congress brought a birthday cake, while well-wishers added more posters and flowers to the mountain of tributes outside the hospital, ululating and breaking out into freedom songs from the struggle against apartheid.
Desmond Tutu, the retired archbishop of Cape Town, Nobel Peace Prize laureate and icon of the struggle against apartheid, spent his morning painting the walls of a school in a shantytown.
A community group in Mpumalanga spent the day building a library for an elementary school in the impoverished town of Nhlazatshe, installing five computers and shelves full of books.
South Africans of all races joined hands in human chains across the country, a symbol of Mr. Mandela's enduring vision of a country where all people, regardless of race, were equal citizens.
At Piet van Vuuren Primary School in Brixton, children armed with black garbage bags trooped out to clean up litter from the surrounding streets. Other students donated blankets to people living in shacks in the nearby Joe Slovo Informal Settlement.
None of the school's students were even born by the time Mr. Mandela stepped down from the presidency in 1999, and some were born after Mr. Mandela retired from public life in 2004. But his name, his image and his message still resonate, said Ashleigh Marie Hedin, 12, a seventh grader.
"Madiba is always with us," she said. "He gave us freedom."
Ms. Mandela-Motlhajwa, a daughter of Mr. Mandela and his former wife, Winnie Madikizela-Mandela, called his birthday "a gift to the nation."
"There are some prophets of doom who say the country will come to a standstill" when he dies, she told a local radio station. But, she said, "the country will continue as it has always done. If anything, the country will solidify, come together and carry on."
Lydia Polgreen reported from Johannesburg, and Alan Cowell from London.
This article originally appeared in The New York Times.