Being wordless is something that can go either way in graphic novels. Either the images will command your will by their intricacies and majesty, or the esoteric nature of the images, or the mundane quality of their subject matter, will give your thumb a rapid little workout (but wouldn't you rather be playing PS3?).
Jens Harder's Leviathan is, so far, for me, the high water mark of wordless sequential art. The story, which is shockingly lucid, concerns the exploits of a...can you guess?
A giant, underwater, monster whale-creature. A god of, and above, mortal beings.
It clashes with other such monstrosities, flexes its invulnerability on the humans who unwisely choose to tango with it, swims around (through a display of Kathryn Bigelow-esque, orgiastic vistas), and deals with the existential angst of being the only of its kind and with being virtually indestructible. In Harder's world waves spout up like a company of trumpets, currents surge with the feriocity of violins, and flesh smacks meatier than the tautest timpani.
A quotation from a relevant source, like Melville for instance, begins each chapter to set the mood, to honour Harder's inspirations, and to hint at the tempo for the art in the proceeding pages. Every page is packed with dynamic, daunting images of sealife (the hopelessness of the food chain), and depictions of the leviathan, the god of all creatures.
If doctor's and dentists and lawyers stocked this book in their waiting rooms, I'd...probably get out more.
For more info: http://www.hardercomics.de/