Which hidden painting (e.g. Hazy Maze, Lethal Lava) in Mario 64 took you the longest to find?

[killamch89]

I’ll admit it: tracking down that sneaky “Hazy Maze Cave” painting took me ages. I’d run past the lava pit so many times I memorized every jump spot. Which hidden painting in Super Mario 64 tested your patience the most? Was it the fiery trek to “Lethal Lava Land,” the slippery slopes of “Cool, Cool Mountain,” or the ghostly corridors in “Big Boo’s Haunt”?