Sheffield's City Museum and the Mappin Art Gallery are about to close to enable £17.3m to be spent on a repairs and improvements.
They will be replaced by late 2005 with a single Weston Park Museum which will bring together the two collections.
The City Museum dates from 1875 and is the oldest museum in Sheffield.
Over the years parts of the building have fallen into a state of disrepair.
Learning approach
While is it is closed the main entrance will be re-developed to improve access from Western Bank.
Inside, the collections will be re-displayed in new exhibition spaces and the 1960s Mappin extension will be demolished.
Nick Dodd, the chief executive of Sheffield's galleries and museums, told BBC Radio Sheffield that they aim to create a new approach to learning.
"It's going to be about young people, it's going to be about families," he said.
"It's about the experience you can have in a gallery of discovering new things."
Funding for the restoration is coming from the Heritage Lottery Fund.