Look out from their deck and the Chesapeake Bay spreads out in sun-glittered splendor, an azure expanse punctuated by sailboats and seabirds and far in the distance the wooded shoreline of Maryland's Eastern Shore.
Look down from their deck, 100 feet nearly straight down, and try not to lose your lunch.
Tony Vajda is manufacturing hollow concrete domes that he will drop offshore in hopes of slowing erosion.
The spectacular view is what attracted retirees Marcia Seifert and Phyllis Bonfield from Philadelphia to the top of Calvert Cliffs in Southern Maryland five years ago, but they didn't realize it would get quite this dramatic. Their two-story home is now 12 measly feet from the edge of the precipice, about 35 feet closer than it was two years ago.
The inexorable erosion of the cliff face has sloughed off massive slabs of earth and trees, and because an endangered beetle happens to live in the cliffs, the residents have not been allowed to stop it.
"It's scary," said Bonfield, looking down the dizzying sand and clay cliff face.
"We don't know how long Mother Nature will allow us to be here," Seifert said.
Erosion is like receding gums or the depreciation of cars. It is a slow battle and one you most surely will lose. And along the circuitous 7,700 miles of Chesapeake Bay shoreline, the wind and waves are winning in ever more emphatic fashion. Geologists say sea levels in the bay are rising about one to two feet per century -- a rate double the world average -- although they do not agree how much is because of global warming and how much because the land is subsiding.
Add to this storm water rushing down from an increasingly developed coastline, and scientists find that land in many spots is falling into the sea at a rapid clip. Every century, an area roughly the size of the District is being lost around the Chesapeake Bay. Each year, about 260 acres of shoreline disappear from Maryland alone. Populated islands that once speckled the bay have been submerged and swept away.
"When you're raising the water level, you just have so much more susceptibility to any kind of wave attack," said Court Stevenson, a professor at the University of Maryland Center for Environmental Science's Horn Point Laboratory in Cambridge.
In such places as Calvert Cliffs, erosion happens in fits and starts. After the bay licks away the toe of the cliff, a big storm or prolonged rains can saturate the top until it cannot bear its own weight and crashes down.
This month marks the start of hurricane season; two years ago, the surge of Hurricane Isabel tore 20 acres of land from the Chesapeake's western shore. This time around, the cliff dwellers of Chesapeake Ranch Estates said they worry about when their number might be up.
"Calvert County is already the smallest county in Maryland, and it's getting smaller every day because it's falling into the bay," said John Eney, president of Chesapeake Ranch Estates, which has 3,700 homes, including 100 perched on the lip of Calvert Cliffs.
