That's all I could see as I slowly moved my hand to feel the edge of the chamber. I'd lost track of time. Had it been 15 minutes? 30? An hour? My heart pounded as I wondered how much longer I had ...

The Latin definition of camera obscura just means "dark chamber," so any dark room or container could technically be considered a kind of camera obscura, but there's realistically a bit more to it ...

THE RACE TO BUILD THE QUIETEST ROOM. The world’s first anechoic chamber, built in 1947 in Murray Hill, Massachusetts, held that title for years.