Coastguard Beach, Massachusetts
Sunrise paints the sky pale orange over Coastguard Beach in Cape Cod, Massachusetts. More than half of all U.S. residents live in coastal counties—and that figure is expected to continue climbing, according to the National Oceanic and Atmospheric Administration.
The line where land meets water is constantly changing and reshaping.
The coastline, that narrow strip of land that borders the sea along a continent or an island, is an ideal place to see a constantly-changing landscape. The nonstop wave action there means nothing ever stays the same. Breakers gnaw away at cliffs, shift sand to and fro, breach barriers, build walls, and sculpt bays. Even the gentlest of ripples constantly reshape coastlines in teeny, tiny ways—a few grains of sand at a time.
Waves are the busiest sculptors on the coastline. Built up by winds far out at sea, they unleash their energy and go to work when they break on the shore. The upward rush of water, called swash, delivers sand and gravel to the beach. On the return, backwash