"immense event" is a correct and usable phrase in written English.
You can use it when you are referring to an event of great significance or importance, such as a major public gathering or an event that causes a large-scale impact on its participants. For example, "Organizing such an immense event in the middle of a pandemic was a tremendous feat that will be remembered for years to come."
Obviously, it will take a long time for that immense event to soak into the cultural fabric: to turn from news into memory, from memory into history, and then -- who knows how, or even if?
Zinedine Zidane also headbutted Marco Materazzi that day an immense event in Internet history.
Whereas in the past, one could pass on the "responsibility" for future-related decisions to the trend or to the predicted phenomenon – in other words pass it off: "that will come!" – such exoneration is no longer valid today: in the immense event forest of modern complexity, the individual trees are now barely discernible.
John, for such an immense event to be accomplished in the life of the church, there are many experts that must be involved in organizational and other responsible tasks.
Initially the composer felt unsure how to respond, even indirectly, to so immense an event as 9/11.
"The economic benefit, not to mention the excitement and legacy of such an immense sporting event would have on this area, is massive".
Supervolcano is an informal term to describe an immense eruptive event that expels in excess of a 1,000 cu km of rock and ash.
Part of the struggle is to put a name to this immense and indecent event.
Even as a mere spectacle, it's absolutely breathtaking and a fitting finale for a strange, immense and unforgettable event.
Gregory Crewdson's set-up photographs are built like no other photographer, witnessing in immense detail dramatic events unfolding in mundane suburban settings.
The protest on October 15th turned out to be an event of immense proportions.
