For me I'm pretty sure it is "LOTR: The Return of the King" with a run time of 201 minutes. I'm just asking since I recently read a pretty interesting article about how the 3+ hour theatrical release might soon be a thing of the past due to declining attendance and stiff competition from the streaming services.

“Whoever fights monsters should see to it that in the process he does not become a monster. And if you gaze long enough into an abyss, the abyss will gaze back into you.”