JAPAN (AP) —Japan's Prince Hisahitowas formally recognized as an adult on Saturday in an elaborate ceremony steeped in imperial tradition. He could be the royal family's last heir. The only son of Crown Prince Akishino,Hisahito, 19, is second in line to the Chrysanthemum Throne. With Japan's male-only succession rules and shrinking royal family, the monarchy faces a looming crisis that mirrors Japan's rapidly aging and shrinking population.The university freshman, passionate about dragonflies and urban ecology, shoulders the burden of a 1,500-year dynasty's future. Proposals to allow female emperors or adopt heirs from former royal branches have stalled, leaving Hisahito at the center of an unresolved national debate. — This is a photo gallery curated by AP photo editors.