As we go about our daily lives, we have a fairly reasonable expectation that the objects around us will continue to maintain their structural integrity. That subway tunnel will keep its shape; that bridge will stay up; that elevator to the 39th storey isn't going to plummet earthwards, unless you ask it to.

Engineers tasked with ensuring public safety do a remarkably good and thorough job. But there have been moments when all was not well, and the results have been shocking – for instance, when what appear to have been design failures led to one of the oddest man-made disasters of the last century: The Great Molasses Flood of 1919.

An enormous steel tank containing 2.3 million gallons (8.7 million litres) of molasses was a familiar landmark in Boston’s North End, looming above a playground, a fire station, and private homes. The molasses came from the West Indies to be converted into industrial ethanol by the tank's owner, the US Industrial Alcohol Company, who had been selling it for use in munitions for the Great War.