Brazil Mourns Architect Niemeyer's Death Internationally renowned architect Oscar Niemeyer was being honored Thursday with a memorial in Brasilia, the modernist Brazilian capital he helped designed out of the country's vast interior plain with signature buildings of flowing concrete and grand, sweeping curves. Niemeyer's remains were flown by presidential plane to the capital from his native city Rio de Janeiro, where he died Wednesday night at age 104. Elisa Barboux, a spokeswoman for the Hospital Samaritano in Rio, said the cause of death was a respiratory infection. After the flight in the plane loaned by President Dilma Rousseff, the remains of the groundbreaking architect were to rest in the presidential palace, a deceptively simple building of glass and concrete that seems nearly weightless, an airy glass structure held aloft by vast, curving white pillars. After a vigil and public visitation, his remains will be returned to Rio for burial Friday. Rio's governor, Sergio Cabral, called for three days of mourning. "His manner was gentle, his convictions were firm, and he was loved by the Brazilian people," Cabral said in a statement. Born into an elite family, Niemeyer was a lifelong communist who took a stand against social inequality in one of the most unequal nations on Earth, though he held no illusions his work could create a more egalitarian nation. Rousseff described Niemeyer as "revolutionary," saying in a statement that he was "the mentor of a new architecture that was beautiful, logical, and as he himself defined it, inventive." Sergio Magalhaes, president of the Brazilian Institute of Architects, said: "Beyond being an architect, Niemeyer was a man ahead of his time, who stood in solidarity with the people and who was loved as few have been." The coffin containing the remains of Brazilian architect Oscar Niemeyer is loaded on a plane bound to Brasilia at the airport in Rio de Janeiro, Brazil, Thursday, Dec. 6, 2012. Niemeyer, 104, the groundbreaking architect who designed Brazil's futuristic capital and much of the United Nations complex, died Wednesday night in Rio de Janeiro, the seaside city where he was born and where his remains will be buried after he is honored with a service in Brasilia at the presidential palace he designed. (AP Photo/Felipe Dana) Close In works that ranged from Brasilia's crown-shaped cathedral to the undulating French Communist Party building in Paris, Niemeyer shunned the steel-box structures of many modernist architects, finding inspiration in nature's crescents and spirals. U.N. Secretary-General Ban Ki-moon said Thursday that Niemeyer's work in designing the United Nations headquarters complex "stands as his legacy to the world." The U.N. chief called Niemeyer "a towering figure" who was outstanding not just because of his stamina and talent but because "he imbued his work with a powerful sense of humanism and global engagement." Niemeyer was one of a group of internationally renowned architects, including France's Le Corbusier, who designed the iconic 39-story U.N. complex that is now undergoing renovation. Nor straight, hard and inflexible lines created by man," Niemeyer wrote in "The Curves of Time," his 1998 memoir. As the city grew to 2 million, critics said it lacked soul as well as street corners, "a utopian horror," in the words of art critic Robert Hughes. Niemeyer shrugged off his critics - and kept working until the days before his death, with engineers visiting his hospital room to talk over pending projects. His admirers said Niemeyer's work make him an eternal figure, whose influence on his nation won't fade. "A few days ago, I heard something I really liked - Oscar will never die," Paulo Enrique Paranhos, who leads the Brasilia branch of the Brazilian Institute of Architects, told the Globo TV network. It's not an exaggeration for those of us who love architecture. Associated Press writers Bradley Brooks in Sao Paulo and Juliana Barbassa in Rio de Janeiro contributed to this report.