However, despite sharing 10 European Cup triumphs - AC Milan's seven successes is second only to Real Madrid in the all-time list - neither have reached the semi-final of a European competition since 2010.

Two decades have passed since they met in the semi-final of the Champions League, when Andriy Shevchenko's away goal proved decisive for AC, who went on to beat Juventus on penalties at Old Trafford in the final.

The tie will allow for the iconic shots of a stadium - Stadio Giuseppe Meazza to give it the proper title - known all over the world for its distinctive red girders, that was initially opened in 1926 and most recently modernised for the 1990 World Cup.

On the outside, the structure is awesome. But inside, it is a relic. Neither club sees a future there but, as BBC Sport outlines, getting out is proving problematic.

Cathedral plans grind to a halt

Inter first started talking about the possibility of leaving the San Siro eight years ago. Four years ago, they joined forces with AC Milan in determining it was something that had to happen.

Structurally, the current stadium would be expensive to renovate. Aesthetically, the costs would soar. Many of the seats remain from the 1990 upgrade. Toilet facilities are basic. The two clubs look on in envy at how English clubs can boost their revenue through their corporate facilities.

In 2022, the Deloitte Money League showed Inter generated €44m (£38.48m) in matchday income. AC Milan generated €32m (£27.99m). By contrast, Tottenham, in their new stadium, generated €125m (£109.3m).

Some of this disparity was due to Covid regulations lasting longer in Italy but nevertheless, neither Milan club can get anywhere close to Tottenham's matchday revenue with the stadium configured the way it is.

The clubs proposed a solution.

After putting out a worldwide tender, renowned stadium designers Populous came up with the chosen model. Dubbed 'The Cathedral', a completely new stadium was planned to be built on land less than 1km from the current structure.

In announcing the plans in December 2021, the two clubs said the area around it would be 'dedicated to sport and leisure', incorporate 110,000sqm of green space and would be the first 'net-zero carbon arena in the world'.

The stadium capacity would be 65,000, 10,000 less than the San Siro. The plan was to present final proposals late in 2022.

But the project has stalled. Protests, appeals and objections meant it ground to a halt. Neither club were willing to invest anything to advance the scheme with no guarantee it would eventually be cleared to be built.

In September last year, the municipality opened a public debate on the stadium that lasted until November. They then advised the clubs that changes to their initial proposals had to be made.

By that point, Inter and AC were starting to look at alternatives.

Inter are looking at a site in Assago, a small town to the south of Milan. AC are assessing a number of options, at San Donato and Sesto San Giovanni, which are both on the outskirts of Milan and La Maura, the site of the horse racing track close to the San Siro.

However, there are issues with all three options. Environmental concerns may scupper the latter.

Questions have also been raised around the financing of standalone projects, although Inter are adamant they do have access to funding and AC Milan's American owners Red Bird are committed following up on predecessors Elliott Investment's belief a new stadium is essential for the club to keep pace with fellow European heavyweights.

What happens now?

The San Siro was modernised before the 1990 World Cup

Inter and AC Milan have shared the Guiseppe Meazza since 1947. Evidently, there are plusses and minuses to this situation. It allows costs to be shared but means parts of the stadium need to be changed to represent the colours of the club who is actually playing.

Being free of these restrictions by going it alone is attractive. However, it is also expensive.

In addition, as the municipality also has a significant input, agreeing lucrative naming rights deals are a non-starter.

But only four Serie A clubs - Juventus, Atalanta, Udinese and Sassuolo - play in their 'own' grounds and it does seem the Milan duo would prefer to remain together in the San Siro area if it was possible.

Last month they were given 90 days by Mayor Beppe Sala to state whether they were going to make the requested alterations to The Cathedral or not.

It is accepted the initial plans will have to be changed considerably but the clubs have already requested an extension as they do not feel they have been given enough time to both assess the practicalities of the changes they are being asked to make and work out the viability of the alternatives.

The issues for all sides are complex. Two of Europe's biggest clubs need a new stadium, local politicians know the exit of the pair would be a blow to the prestige of the area as well as costing vital income. The talking continues and no resolution is in sight.

In the meantime, the San Siro remains as it has been since 1990. Striking on the outside, a concrete hulk underneath.