Plans have been unveiled to renovate Chicago's iconic Willis Tower (formerly the Sears Tower). The skyscraper's $500 million modernization is being led by Gensler and will involve the addition of plush new tenant-only amenities, an upgraded observation point and a three story glass structure at its entrance.

Originally designed by Skidmore, Owings & Merrill, the Willis Tower was an amazing engineering achievement when completed in 1973 that still impresses almost half a century later.

GET 30% OFF NEW ATLAS PLUS

Read the site and newsletter without ads. Use the coupon code EOFY before June 30 for 30% off the usual price.

BUY NOW

It reaches a height of 1,451 ft (442 m) and was the world's tallest building from completion until being surpassed by Kuala Lumpur's Petronas Towers in 1998. It's still the USA's second-tallest tower, after SOM's One World Trade Center, and is currently rated 12th tallest in the world by the CTBUH.

Gensler's renovation plans will transform the Willis Tower's plaza in an attempt to make it more inviting to passersby. A large new three story glass structure will be installed atop the skyscraper's existing stone entrance and three subterranean floors will also be added, in addition to a winter garden with unobstructed views of the tower. New retail, dining and entertainment spaces will be created at the base of the building, too.

Additional changes include the reconfiguration of existing floorspace within the tower to produce new exclusive tenant amenities, such as a fitness center, lounges, private event space and concierge services.

A substantial new outdoor deck and garden space will also be created and the building's existing 103rd floor glass-bottomed Skydeck Chicago observation boxes will be upgraded, though we've no word on what exactly this will entail.

The renovation plans were announced by Chicago mayor Rahm Emanuel, alongside developers Blackstone and Equity Office. Gensler will be working with Gonzalez Architects, Hetzel Design, and Turner Clayco. Work is due to begin on the renovation project later this month. The expected date of completion has not been revealed.

Source: Willis Tower

View gallery - 13 images