It is not often, hardly ever in fact, that Chelsea FC get a whole post for them dedicated. But honour where honour is due.
The club from the Fulham Road have made history. This alone justified some words written about them.

By winning the Europa Conference League final against Real Betis 4-1, the Bluds have become the first club to have won all European cup competitions. This contains the old Cup Winners Cup as well as the Europa League.

Moreover, they have won these European Competitions twice, except the Conference League.

It is also important to note that Chelsea declined the offer to participate in the European Cup in 1955. Back then, the Football Association of England did not think much of those fancy Europeans and influenced Chelsea in a way they had no other option than to withdraw from the competition. Who knows, their history might have been different.