AC Milan and Inter have presented two proposals for the renovation of their San Siro stadium.
A preparatory document for the stadium's feasibility project have been submitted to the Municipality of Milan.
Two different projects are being considered.
The San Siro was originally opened in 1926, with its last major renovation taking place ahead of the 1990 World Cup.
In 2015 it appeared as if Milan and Inter would be going their separate ways and building new stadiums of their own.
Milan mayor Giuseppe Sala originally didn't want to see the old stadium completely demolished, but the clubs say maintaining it will no longer be possible.
"Its structure has been modified many times during its life and cannot be expanded further to the East due to unmovable property borders", their proposal website states.
"Moreover, the stadium would undergo a radical transformation, rendering it unrecognisable from its current form and also failing to comply with international capacity, accessibility and sustainability standards."
Perhaps of more pressing concern to fans of both clubs, they add, "Refurbishing the existing structure would involve years of home games played hours outside of Milan."
Populous - the company behind the Tottenham Hotspur Stadium, and the Parc Olympique Lyonnais - have presented one design called 'The Cathedral'.
The other design has been put forward by MANICA/Sportium who are behind the Allegiant Stadium in Nevada, which is soon to be home to the Raiders NFL franchise.
Their's is entitled 'The Rings of Milano'.
Both concepts, "provide for the retention of a part of the current Giuseppe Meazza Stadium within a new retail and sports district that can be used 365 days a year, including about 106,000 square metres of green space."
It's hoped the completed stadium can form part of the 2026 Milan-Cortina Winter Olympics.
A joint-statement adds, "FC Internazionale Milano and AC Milan believe it is essential, especially in light of the current moment, to commence a project that represents more than one billion euros of private investment, which will generate thousands of new jobs and serve as a cornerstone for the future development of the city of Milan and Italian football."