<p><br> 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.</p>

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.

Photograph by Michael Melford

Coastlines

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

DON'T MISS THE REST OF THIS STORY!
Create a free account to continue and get unlimited access to hundreds of Nat Geo articles, plus newsletters.

Create your free account to continue reading

No credit card required. Unlimited access to free content.
Or get a Premium Subscription to access the best of Nat Geo - just $19
SUBSCRIBE

Read This Next

Did this mysterious human relative bury its dead?
This new birth control for cats doesn't require surgery
How the Zoot Suit Riots changed America

Go Further

Subscriber Exclusive Content

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet

Why are people so dang obsessed with Mars?

How viruses shape our world

The era of greyhound racing in the U.S. is coming to an end

See how people have imagined life on Mars through history

See how NASA’s new Mars rover will explore the red planet