"The End of the World as We Know It!"
Triangle 1998-17. Continued from Superman (1987) #134 (16), Teen Titans (1996) #19 (16.1) and Supergirl (1996) #20 (16.2) and continues in Steel (1994) #50 (17.1) and Action Comics (1938) #744 (18).
Cover (center) connects with Steel (1994) #50 (left) and Action Comics (1938) #744 (right) to form the bottom row of a larger puzzle image from all nine Millennium Giant issues.