Apocalypse beast from FF/Iron Man: Big in Japan was pretty big. Iron Man stated it was atleast 3 miles tall.
It's finger in relation to the city of Tokyo:
It's so big that humans can fit in its pores:
What it looks like in relation to the island of Japan:
It's face(?) in relation to a volcanic island:
It was large enough that a race of humanoid beings called Moloids were able to live in it for more than 10,000 yrs before the resources were depleted: