At any given moment, about 15,000 men and women are living in solitary confinement in the federal prison system, housed in tiny cells not much larger than a king-sized bed.
"It is hard to describe in words what such a small space begins to look like, feel like and smell like when someone is required to live virtually their entire life in it," says Craig Haney, a psychologist at the University of California, Santa Cruz.
But Tuesday, Haney, who has studied life inside prisons for three decades, had an opportunity to paint that picture.
I've never in my life desired a low-sodium biscuit, but I let the well-groomed woman at the Fancy Food Show in Washington, D.C. this week goad me into eating one.
"They're soooo good, I swear," she says.
It's perfectly fluffy and edible, this low-sodium biscuit, but seconds after it's gone I'm regretting having just wolfed down the whole thing. That's precious space in my stomach that I've just forfeited for an unremarkable food I'd never be interested in eating again.
The federal government could soon give the final go-ahead for Royal Dutch Shell to begin drilling for oil in the Arctic Ocean. Shell has spent $4 billion since 2007 to prepare for this work, and is hoping to tap into vast new deposits of oil.
But the plan to drill exploratory wells is controversial — opposed by environmental groups and some indigenous people as well.
Advocates for prisoners rights say too many inmates spend years in solitary confinement — in violation of the constitutional bar against cruel and unusual punishment. Today, they persuaded the U.S. Senate to hold the first hearing on the issue, as state and federal prison systems fend off new lawsuits over the practice.