The Index is a mixed-use skyscraper designed by Foster and Partners currently under construction in Dubai, United Arab Emirates. The supertall will be 328 meters (1,076 feet) tall and have 80 floors. Of those 80 floors, the lower 25 will be offices and 47 will be for residential use, including the world's highest apartment for a time when construction ends in 2008. The tower is oriented in such a way that the eastern and western concrete cores shelter the floors from the harsh, desert sun and the climatic effects of the area. The south-facing facade will utilize extensive sun shades to lower solar gain. A double height sky lobby will separate the offices and apartments; recreational facilities like a swimming pool, gym, and restaurants will be located on the sky lobby.