Known as the Emerald City, Seattle, Washington, got a different sort of cut gem when the new $165 million Central Public Library opened downtown in 2005. That library, designed by influential Dutch architect Rem Koolhaas, was an instant hit drawing 8,000 visitors a day the first year after opening its doors. With great glass walls reflecting the distant mountains and an interior space that is more reminiscent of a high-tech airport than musty book repository, it&rsquos little wonder folks in the high-tech hub of the Pacific Northwest flocked to the new building. Key features include the Dewey Ramp, a four-storey sloping walkway that allows visitors to explore the collection of more than a million books, and the 10th floor view of downtown and nearby Elliot Bay. The library offers free public tours, first-come first served. See www.spl.org.