Roads on Hawaii’s Big Island are often flanked with miles of "Island graffiti," like this love note. Instead of spray paint though, bits of white coral harvested from local beaches are arranged into messages, which seem to glow against the island's black lava expanses.

But tourists beware: Removing the coral from beaches is illegal. And disturbing an already-posted message is considered rude and supposedly brings bad luck.

(Photo shot on assignment for, but not published in, “Kamehameha: Hawaii's Warrior King" November 1983, National Geographic magazine