View Larger Version | A one-day, round-the-clock thermal study of Phoenix buildings, including the U.S. Bank Center, tracked how concrete and glass absorb heat by day and release it by night. Deep purple is 9°C, deep orange is 17°C and white is at least 25°C. Throughout the night, the building, especially near street level, remained warmer than the surrounding air. Credit: Di Sabatino et al./Arizona State University