Photos: Sizing up Chicago's green high rises

The Greenbuild convention attracted more than 22,000 attendees and was held at the new McCormick Place West, which opened under budget in August as the largest new building yet to achieve LEED certification.

Among its eco-friendly features are a 14,000-square-metre roof garden; drip irrigation systems; energy-efficient lighting; and recycled, locally bought building materials. A 945-metre-long tunnel is designed to channel 208 million litres of storm water into Lake Michigan each year.

Credit: Gregory Wenzel