Nicknamed Lo Storto, or, The Twisted One, Zaha Hadid Architects' (ZHA) 44-storey tall tower joins Arata Isozaki's 202-metre high Allianz Tower, which completed in 2015.
Studio Libeskind's 175-metre tall PwC tower will complete the trio of skyscrapers when it completes in 2019.
A helical twist runs through the tower, with each rhomboid-shaped floor plate aligned to gently shift the tower around its vertical axis. The twist reduces as the levels ascend, so that no two stories are completely aligned.
This curvilinear form is intended to represent the centripetal forces of the three axises of the city converging at its base, creating a vortex.
Due to the twist, the topmost floors are orientated to have southeasterly views of the Santa Maria delle Grazie, a 15th century church and UNESCO World Heritage site.
Inclined white columns running up either side of the twist provide a visual link to the white podium below that extends to the rear of the tower and holds a retail and cinema complex.
A double-facade of louvres and glazing deflect the sun, providing environmental control for each floor. The building has been awarded LEED Platinum certification.
When occupied the tower will host 3,900 employees of the Generali Group, an Italian insurance company that is the third largest in the world. Its interiors are due to be completed this summer.
Each of the architects is responsible for one of the landmark towers that will be surrounded by new homes, parks and and shopping areas.
Due to complete in 2020, the 16 hectares of CitiLife development will host 1,000 new homes, office space for 11,000 workers, a 42-acre public park, piazzas and a kindergarten.
The new Tre Torri station on the Milanese metro system will connect Line 5 to the site.
ZHA, which was founded by the late Zaha Hadid and now led by Patrik Schumacher, has recently unveiled designs for a number of signature curvaceous buildings around the world.
In China's Jiangxi province the architects, that were listed at number seven on Dezeen Hot List 2017, have announced plans to build a series of barrel-vaulted classrooms with the assistance of robots.
In Mexico City work has begun on a ZHA residential tower that will rise up from a twisting base, and plans have been submitted in London for a pair of rounded towers projecting upwards from a fluted podium.
Photography is by Hufton + Crow.