The U.N. Habitat III event got under way here Monday with a goal to establish a New Urban Agenda for the next 20 years.

"(I)t is clear that transforming our world for the better means transforming our towns and cities. That means better urban governance, planning and design," U.N. Secretary-General Ban Ki-moon said in his speech to open the United Nations Conference on Housing and Sustainable Urban Development.

"And it means engaging women and girls in making towns and cities safer and more productive for all," he told the gathering in the Ecuadorian capital.

Welcoming the participants to Quito, Ecuador's President Rafael Correa spoke of his government's commitment to the idea of a right to the city, which he defined as the right to live, consume and produce in "just and sustainable" cities.

The secretary-general of Habitat III, former Barcelona Mayor Joan Clos, pointed out that cities have become "the principal engine of development and prosperity."

But he also acknowledged dangers.

"Our analysis of urbanization in the last 20 years reveals that the present urban practices are unsustainable," the Spaniard said, calling for a return to what he called the three basic principles of urban development.

"Urbanization must be based on the rule of law" and must be grounded in good design, Clos said.

The third principle is adequate financing, he said, stressing that "urbanization is an economic phenomenon in which public investment generates a lot of private value."