iPhoneOgraphy – 30 Jan 2016 (Day 30/366)
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.
Manhole covers date back at least to the era of ancient Rome, which had sewer grates made from stone.
Manhole covers are often made out of cast iron, concrete or a combination of the two. This makes them inexpensive, strong, and heavy, usually weighing more than 50 kilograms (110lb). The weight helps to keep them in place when traffic passes over them, and makes it difficult for unauthorised people not having suitable tools to remove them.
Manhole covers may also be constructed from glass-reinforced plastic or other composite material (especially in Europe, or where cover theft is of concern). Because of legislation restricting acceptable manual handling weights, Europe has seen a…
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