For the body of the building, the architects chose the Chinese symbol for earth, a square, and sky, a circle. It's a common misconception that the original moon gate opening was the "sky" symbol.

Unlike other buildings, such as the Shanghai Museum and the Shanghai Grand Theater, which literally places a circle on top of a square, the SWFC combines the two shapes much more subtly.

With 70 floors dedicated to offices, 14 to hotel space, and the rest to entertainment and observation decks, the building had three types of space requirements. While offices ideally require large floor space shaped like a square doughnut, with the core cut out for elevators, a hotel requires a thinner rectangular shape for a central corridor opening onto small rooms.

"To get the ideal dimensions for both offices and hotels, we placed a rectangle shape diagonally across a square base, so that the building tapered to a thin ridge at the top. The heavy base tapering to a light rooftop dramatizes the tall building as a link between the earth and the sky. We also cut circular arcs into the building to create the tapering, which represents a cosmic arc, the circular symbol for the sky."

The curve creates different-sized offices.

"With smaller floor space further up, it caters to the habits of different clients," says Kohn. "For example, Americans like bigger offices, whereas Europeans prefer smaller ones."

The aesthetic symbolism is practical as well. Pedersen designed the smooth, glass-covered exterior with practical energy efficiency in mind.

"We wanted to reduce the energy consumed by the materials used in the building - what we call embodied energy. Jin Mao Tower, for example, has hundreds of corners, tremendous amount of texture which all requires energy to create. Our building is by contrast powerful in its shape but very economical in its use of material."

Having designed more than 30 projects in China, Pedersen is proudest of the Shanghai World Financial Center.

"I'm over 70 and at the end of my career. I've never had an opportunity to design something like this - very few architects get that opportunity. Not so much because of the height, but in the way it represents the future of highrises. It's a city within a city, and when you're in it you have almost everything available to you. It's an example of what tall buildings can be."

Despite its elegance, reviews by city residents are somewhat unflattering. While the Jin Mao Tower is recognizably inspired by a pagoda, the trapezoidal opening at the top of the SWFC has been compared to a humble bottle opener on the grand skyline.

The architects laugh, a bit awkwardly. "Well, that wasn't the intention," says Kohn.

Shanghai's Lujiazui skyline is not finished yet. The Jin Mao Tower and the Shanghai World Financial Center are two in a planned trio of super-tall structures. The third tower is planned to be 80 meters taller than the SWFC. Construction has not started and completion depends on the economy.

China, and Asia in particular, has already overtaken New York as home of skyscrapers.

"It makes sense with urbanization to build tall and on top of subway lines so people can get to the building," says Pedersen. "It's happening all over Asia, and it will happen all over the world. It's the most energy-efficient way."

Energy efficiency aside, what does highrise living mean for lifestyles and human communities?

"From our perspective, Asians are more comfortable with highrises than almost any other cultural group," says Pedersen. "My sense is that Asians feel comfortable living in cities because of their family structure - they are used to the give and take of living densely together."

(Shanghai Daily November 19, 2008)