Oscar Niemeyer, the Brazilian architect who collaborated on the design of the United Nations headquarters in New York and designed Brazil’s capital city, Brasilia, died on Wednesday. He was 104.

Niemeyer had been battling kidney ailments and pneumonia for nearly a month in a Rio de Janeiro hospital, according to a hospital spokesperson.

'I am attracted to free-flowing sensual curves. The curves that I find in the mountains of my country, in the sinuousness of its rivers, in the waves of the ocean, and on the body of the beloved woman'— Oscar Niemeyer

A towering patriarch of modern architecture, he was known for his inventive, curved designs often in undulating concrete, which he said were inspired by his love of the female form.

"I am not attracted to straight angles or to the straight line, hard and inflexible, created by man," he said famously. "I am attracted to free-flowing sensual curves. The curves that I find in the mountains of my country, in the sinuousness of its rivers, in the waves of the ocean, and on the body of the beloved woman."

His distinctive modernist buildings can be found around the world, including the Communist Party headquarters in Paris, the flying-saucer-like Museum of Contemporary Art in Niteroi, Brazil, the University of Haifa, and the headquarters of the Mondadori publishing company in Italy.

Designing Brasilia

His greatest influence was on Brazilian architecture. In the 1950s, he worked with urban designer Lucio Costa to design the federal capital, a planned city that opened in the 1960s on a formerly undeveloped central plateau.

Brazil's National Congress, designed by Brazilian architect Oscar Niemeyer and inaugurated in 1960, in Brasilia, Brazil. (Eraldo Peres/Associated Press)

It features his architecture throughout, including designs for the National Congress and presidential residence.

He won the 1988 Pritzker Prize, considered the Nobel Prize of architecture, for his design of the Roman Catholic Church in Brasilia. Its “Crown of Thorns” cupola fills the church with light and a sense of soaring grandeur despite the fact that most of the building is underground.

Niemeyer, born Dec. 15, 1907 in Rio de Janeiro, began work in his father’s typography business and was a draftsman for local architects.

In the 1930s, he began designing as an intern with Costa and made his mark with a series of buildings for Pampulha, including the Church of St. Francis of Assisi, which brought him to international attention.

Friend of Le Corbusier

He was invited to work with Le Corbusier and others on the UN building and the Swiss-French architect remained an influence throughout Niemeyer’s life.

His work is celebrated for innovative use of light and space and for his sculptural use of reinforced concrete.

Statues of the apostles are seen in front of the 'crown of thorns' of the Cathedral of Brasilia, an architectural landmark that earned Niemeyer the Pritzker Prize. (Eraldo Peres/Associated Press)

“That is the architecture I do, looking for new, different forms. Surprise is key in all art,” Niemeyer told Reuters in an interview in 2006. “The artistic capability of reinforced concrete is so fantastic — that is the way to go.”

Niemeyer held strong pro-communist views and was a close friend of Cuba’s revolutionary leader Fidel Castro. He left Brazil after the 1964 military coup and opened an office in Paris, not returning to Brazil until 1984, after the end of the 21-year military dictatorship.

Politicians were willing to overlook his communist sympathies to enjoy his designs. Georges Pompidou, the right-wing Gaullist former French president, called Niemeyer’s Communist Party of France headquarters in Paris, “the only good thing those commies ever did.”

Criticisms of planned city

Brasilia today is criticized for its rigid divisions into “hotel,” “government,” “residential” and even “mansion” districts, which make it difficult to find groceries. It also has a strict divide between rich and poor residents, but Niemeyer distances himself from that development.

“It seemed like a new era was coming, but Brazil is the same crap — a country of the very poor and the very rich,” he said in a Reuters interview in 2001. He also blamed Costa for the rigid urban design.

“I just did the buildings,” he said. “All that other stuff was Costa.”

In his memoir The Curves of Time, Niemeyer tells of a life rich with practical jokes, high jinks, partying and women. The 1964 French movie L'homme de Rio (The Man From Rio), starring Jean-Paul Belmondo, celebrates his designs.

Niemeyer was married for 76 years to Annita Baldo, his first wife. He is survived by his second wife, long-time aide Vera Lucia Cabreira, who he married in 2006 at the age of 99, and by four grandchildren.

Niemeyer’s only daughter, an architect, designer and gallery owner, Anna Maria, died on June 6 at the age of 82.