Aquaman #53

That dramatic cover by Nick Cardy says it all — a coastline city tilts catastrophically into the ocean while Aquaman, clad in his orange-and-green costume, strains to hold back a massive yellow structure as panicked civilians scramble for safety around him. Below the waterline, figures drift in the chaos, giving the image a striking split-world composition that puts the Sea King's domain front and center. With Steve Skeates writing and Jim Aparo on full art duties inside, this 1970 DC issue poses one of the more unsettling questions a cover could ask.