CALIFORNIA – Tyree Johnson loved his apartment that overlooked the Pacific Ocean — until it started to crumble down a cliff into the sea.

For 15 years, he could enjoy sunsets over the water from his back porch in Pacifica, a few miles southwest of San Francisco.

Pods of dolphins swam by and hang gliders floated overhead. But all that splendor came with a risk: The bluffs were weakening and ocean was gnawing away below.