A manhole cover is a removable plate forming the lid over the opening of a manhole, to prevent anyone or anything from falling in, and to keep out unauthorized persons and material.
They date back at least to the era of ancient Rome, which had sewer grates made from stone.
Read more about Manhole Cover: Description, Circular Shape, Manhole Covers and Race Cars, Propelled Into Space, Other Uses, Gallery
Famous quotes containing the word cover:
“You may call a jay a bird. Well, so he is, in a measure—because he’s got feathers on him, and don’t belong to no church, perhaps; but otherwise he is just as much a human as you be. And I’ll tell you for why. A jay’s gifts and instincts, and feelings, and interests, cover the whole ground. A jay hasn’t got any more principle than a Congressman.”
—Mark Twain [Samuel Langhorne Clemens] (1835–1910)