He is a stoutly built man with an intensity about the eyes and nimbleness of physique that makes it seem he's ready to spring into action at any moment. Were it not for the gray hair, it would be hard to imagine that this man is already 75 years-old.

He is Jaime Lerner, the spiritual force behind the transformation of Curitiba, Brazil. Time magazine listed him, along with Apple Computer's Steve Jobs, among the world's most influential thinkers of 2010.

"The most important thing is just to 'get to work,'" he intones in his booming voice. It was 41 years ago when he became mayor of his beloved city for the first time, at the age of 34, and his passion for Curitiba burns just as hot today.

In those days before free, direct elections, mayors were political appointees who were no more than pawns in the game of power politics and were subject to replacement at any time. For an idealistic young architect like Lerner, retaining the mayor's office was particularly precarious.

Those holding the reins of power at the time were under the mistaken impression that Lerner's youth would make him easy to control. As it turned out, he was no milquetoast, and subsequently set about enthusiastically pursuing reform.

Under Lerner's leadership Curitiba built a "culture of speed." In just 72 hours, the city pedestrianized a downtown shopping district. It built a park larger than Taipei's Da-an Forest Park in just 28 days. The city's Opera de Arame, or Wire Opera House, was built in two months. The high-speed bus system was completed in four years.

The "speed" element was essential, firstly, to prevent bureaucratic lollygagging, secondly, to avoid undue interference of public opinion on policy decisions and, thirdly, to keep policymakers from having second thoughts.

So did the young architect win any hearts with his high-speed, boldly transformative actions?

The answer to that question can likely be gleaned from the three terms Lerner served as Curitiba mayor and having ultimately gone on to serve two terms as governor of Parana, the Brazilian state of which Curitiba is capital.

But becoming a politico had never been the defining intention of this young fellow who stormed onto the political scene by happenstance. His whole original aim had been merely driven by a "desire to make cities more beautiful."

Lerner spent six months combing neighborhood streets and talking with city residents to more intimately acquaint himself with grassroots opinion. He would ask residents: "What are your dreams? What are your needs?"

To find a balance between "the needs of today" and "the development of tomorrow," Lerner forced himself to find the time to contemplate the future of cities. To avoid becoming bogged down in routine daily affairs, he began to divide his days into two parts.

In the mornings, he would go to a separate office to focus on future city development issues. In the afternoons he would head over to his office at city hall to assume his duties as mayor in tackling the day-to-day business of running the city.

People: The Most Important, and Problematic

One Friday evening streets were closed along a 15-block stretch of the bustling downtown area. A high-speed makeover was underway. Cobblestones were laid and trees planted, turning the area into a pedestrians-only zone.

Worried about the impact on their businesses, area merchants began loudly protesting the measure, but Lerner refused to back down.

"The only thing to do was keep communicating," he said.

Today the 15-block downtown pedestrian mall is the pride of city residents. Now called Rua das Flores ("Flower Street"), it preserves a space for leisurely strolling in the heart of the city.

On Saturday mornings, the outdoor painting activities on Rua das Flores give kids a chance to have fun and interact. Pine-shaped markers in the cobblestone pavement indicate the historical buildings that line the walkway, reminding pedestrians to take pause along their way and ponder the past, present and future of this spot.

The similarly historic North Gate in Taipei, by contrast, sits forlornly amidst a maze of traffic flyovers wistfully holding on to its last shred of dignity.

Despite earning international acclaim and becoming a case study for other cities' urban planning efforts, "Curitiba is not paradise," Lerner insists. Many problems remain to be tackled here. "The effort to continue improving the quality of life for people must not stop."

After retiring from public life, Lerner has continued to be active in urban planning endeavors. Asked which of the world's cities he pines for the most, Lerner answers, without the slightest hesitation, "Curitiba!"

Translated from the Chinese by Brian Kennedy