TRAVELER @ nationalgeographic.com

Go in late summer. If it’s one of those humid, drizzly days, the sky the color of the inside of a clamshell, the end-of-summer sadness will hang from your shoulders like a wet, sandy beach towel. This is stingy New England, after all, where all fine things exact a price.

There are, at most, three days all summer, usually in the middle of July, when you can take summertime for granted. On those days—and only on those days—you can say to yourself, “I can stay inside and get some work done” without a twinge of regret.

Even if you’re visiting for the first time, the nervous voluptuousness of the place is palpable. If you’re driving, you’ll be on Route 6, and you’ll pass all the familiar fast-food joints. You’ll pass motels and motor lodges promising heated pools and free HBO; super-sized stores selling beach and Christmas junk; batting cages; miniature golf; go-carts; waterslides.

As you come to the Cape’s elbow, or “crazy-bone,” as Thoreau put it, the names of the towns are so summer New England that you almost hear Ken Coleman reading the road signs over a crackling transistor radio: Chatham, Orleans, Brewster, Eastham. And one more thing about the summer Cape—the Red Sox, on the television, on the radio, in overheard conversations, are as constant and as inescapable as the call of the muezzin in Tangiers.

Near the wrist of the Cape, you come to Wellfleet and the Cape Cod National Seashore.

The 40-mile National Seashore starts in Chatham, but the wild, tumbling dunes of Wellfleet are the heart of this place where, as Thoreau put it, “a man may stand...and put all America behind him.”

The National Seashore is not pristine, as in untouched. The peaks of houses can be seen above the high cliffs of sand, and the beach is dimpled with a million footprints. At the waterline, however, they are washed away, and with America at your back, just over those cliffs, all that faces you is the Atlantic. The surf laps gently at your ankles; a surf that you imagine rippling across the sea from the Old Country of kings and earls, cathedrals, Inquisitions, and crumbling ruins of exhausted civilization. That was the world left behind by the Mayflower nearly 400 years ago.

As the sun descends, long shadows tremble across the sand. Gulls squeal, and a soft wedge of noise—a foghorn—sounds in the distance. Suspended between cliff and sea, this place is touched and hallowed by that miracle of eternal promise that became America.