Architect Rem Koolhaas struck out of some big projects in New York. So where did he go? China. “Every architect in the world right now is looking at China, because it seems to offer limitless opportunity. It’s a place of almost unstoppable optimism—despite this momentary setback from SARS—and immense building projects that are ideally suited for someone who positions himself right on the cusp of change, as [Mr. Koolhaas] does.”