The Thompson Center in downtown Chicago has been given a new facade as part of a renovation for tech company Google by architecture studio Jahn.

Photos taken earlier this month show the largely complete facade of the Thompson Center, which is in the midst of a complete overhaul by Jahn.

Originally designed in the 1980s by Jahn founder Helmut Jahn, the building was considered one of the most significant pieces of post-modern architecture in the USA.

Built for the Illinois state government and named after former Illinois governor James R Thompson, the building was under threat of demolition after plans to sell it were made public in 2015.

In 2022, the building was sold to Google's parent company Alphabet Inc, which decided to undertake a thorough renovation.

The building is set to become Google's Chicago HQ with office space on the upper floors and shops and restaurants on the lower floors.

As part of the renovation, the original, slightly darkened patterned glass that wrapped the building has been replaced by a sleek, uniform curtain wall.

This triple-glazed facade forms part of the strategy to greatly improve the environmental performance of the building.

While renderings released ahead of the renovation showed a transparent facade with clear views into the building from the street, the photos appear to show a reflective finish on the glazing.

Below the sloped, glass facade, the photos show a concrete and brass colonnade that replaced the original red and beige stone finishes.

The renovation of the highly distinctive building will also see the building's central, 17-storey atrium overhauled.

Renderings of the space, which is expected to be open to the public, show a stepped, circular space with restaurants, cafes and workspaces.

The renovation is planned to be completed in 2027, with the building's name changed from the James R Thompson Center to the Thompson Center.

The building was the most famous work designed by long-time Chicago resident Helmut Jahn, who died in a bicycle crash aged 81 in 2021.

The photography is by Tom Ravenscroft.