high-rise buildings, such as the Empire State Building, the surface area provides opportunities for design innovation. New York City has five other high rise green buildings; Bank of America Building (One Bryant Park), Hearst Building, One World Trade Center, The New York Times Building and Condé Nast Building. VOC released from construction materials into the air is another challenge to address. In Milan, a university-corporate partnership sought to produce semi-transparent solar panels to take the place of ordinary windows in glass-facade high-rise buildings. Similar concepts are under development elsewhere, with considerable market potential. The Manzara Adalar skyscraper project in Istanbul, designed by Zaha Hadid, saw considerable innovation as part of the Urban Transformation Project of the Kartal port region. Extreme structures that have received LEED certification include: Amorepacific Headquarters in Seoul by David Chipperfield Architects; Project: Brave New World: SFMOMA by Snøhetta in San Francisco, California; Project: UFO in a Sequinned Dress: Centro Botín in Santander by Renzo Piano; Building Workshop in Zusammenarbeit with Luis Vidal + Architects, in Santander, Spain; and Project: Vertical factory: Office building in London by Allford Hall Monaghan Morris in London. Other related research notes A 2003 analysis of the savings from green building found in a review of 60 LEED buildings that these buildings were, on average, 25–30% more energy efficient. It also attributed substantial benefits to the increased productivity from the better ventilation, temperature control, lighting control, and reduced indoor air pollution. From a financial perspective, several 2008 studies found that LEED for-rent office spaces generally charged higher rent and had higher occupancy rates. Analysis of CoStar Group property data estimated the extra cost for the minimum benefit at 3%, with an additional 2.5% for silver-certified buildings. More recent studies have confirmed these earlier findings in that certified buildings achieve significantly higher rents, sale prices and occupancy rates as well as lower capitalization rates, potentially reflecting lower investment risk. LEED focuses on the design of the building and not on its actual energy consumption, and therefore it has been suggested that LEED buildings should be tracked to discover whether the potential energy savings from the design are being used in practice. Directories of LEED-certified projects The USGBC and Canada Green Building Council maintain online directories of U.S. LEED-certified and LEED Canada-certified projects. In 2012 the USGBC launched the Green Building Information Gateway (GBIG) to connect green building efforts and projects worldwide. It provides