Titanic 3D 4K was great. I've watched that film thousand times but when I watch it in IMAX in 3D 4K, I saw some small details that I've never seen in previous watch.

I dont remember Fern gully having sentient whale-like creatures befriending an outcast blue alien, an immaculate conception kid having connection with the planet, bioluminescent forest and creatures, cool human tech... I doubt you even watched Ferngully.

I love the first Avatar, and Avatar 2 I think is better than the first.