"Ashes to ashes, dust to deep."

With a spray of water, Guy Gleichmann surfaces from a 40-foot dive during which he helped set his mother's remains in their final resting place: a sunken city where brightly hued fish shimmy among fantastical architecture.

"I didn't want to leave," Gleichmann says, doffing mask and mouthpiece. "It's so beautiful down there. It's so serene." The 48-year-old investment manager and diver from Pompano Beach, Fla., wanted a unique and accessible spot for his mother, Emma, who died in December at age 75. So he had her cremated remains mixed into concrete in the shape of a seashell, which was placed near the statue of a lion.

Ashes to ashes, dust to deep.