Standing at 828 meters (2,717 feet), the Burj Khalifa is the tallest structure and building in the world. Its design is derived from the geometries of the Hymenocallis flower and the patterning systems embodied in Islamic architecture. To combat the immense wind forces at such heights, the building features a 'buttressed core' design—a tripod-shaped structure that provides stability and reduces the building's thickness as it rises. One of its most remarkable features is the 'stack effect': the temperature difference between the bottom and the top of the building is about 6°C (11°F). The condensation collected from the building's massive air conditioning system is enough to fill 20 Olympic-sized swimming pools annually, which is then used to irrigate the surrounding parkland.