In terms of sheer number of pages, Jeff Smith's all-ages comic Bone is by far the longest work I've ever recommended on Steemit- and it's more than worth reading all 1332 pages. Bone's won more awards than you can shake a stick at- 41, in fact, including 10 Eisner and 11 Harvey awards. I'm hardly the first to recommend it, nor will I be the last.
Bone tells the story of the three Bone cousins- Fone Bone, Phoney Bone, and Smiley Bone. These three odd, cartoony creatures, exiled from their home in Boneville, end up finding themselves in a mysterious, lush valley, filled with dragons, simple rural folk, rat monsters, and more. They quickly get caught up in an adventure of truly massive scale- pun intended- as they try to protect their new friends and find their way back home. And, unlike so many all ages books, which are really just children's books, Bone is actually an all ages book.
The art style of Bone is, in many ways, reminiscent of Tintin- relatively simple characters over elaborate backgrounds. The divide isn't as strong as Tintin, however, and there's definitely quite a bit of variance in the characters- the Bone cousins are by far the simplest and most cartoony characters, while many of the rural folk, the rat monsters, and more are far more elaborately drawn, often coming close to the background complexity. It's a wonderful choice, especially in black and white. Don't get me wrong, the colored version is still excellent, but I've got a soft spot for a well done black and white book. There are countless Bone fans who prefer the color version- honestly, you can't go wrong either way. (The black and white complete collected version is only about $20, though, while the color is pushing $100.)
Just do yourself a favor already and read Bone. It's well worth your time.