Aqua Tower in Chicago

Under construction in Chicago at 225 North Columbus Drive is a mixed-used building tower, Aqua Tower, designed by Jeanne Gang of Studio Gang Architects and developed by Magellan Development.

Aqua Tower will stand 250 m (819 ft) tall with 82 floors, containing a mix of apartments, hotel rooms, offices and retail space.

From the Studio Gang website

In an increasingly dense city like Chicago, views from a new tower must be negotiated between existing buildings. Aqua tower considers criteria such as views, solar shading and function to derive a vertical system of contours that gives the structure its sculptural form. Its vertical topography is defined by its outdoor terraces that gradually change in plan over the length of the tower. These terraces offer a strong connection to the outdoors and allow inhabitants to occupy the building façade and city simultaneously. The result is a highly sculptural building when viewed obliquely that transforms into a slender rectangle from further away. Its powerful form suggests the limestone outcroppings and geologic forces that shaped the great lakes region.

I think it would have been more appropriate to call it Iceberg. According to the UK Guardian, it is also the tallest building in the world to be designed by a woman.

The balconies do not look safe and it would be a nightmare to people suffering from acrophobia. The railing should be as high as a person's shoulder.

The question remains, how energy efficient is the building?