We sometimes say that two people are so close that they appear ‘joined at the hip’ – metaphorically speaking, of course. But imagine this were a reality. (Indeed, think about how the phrase might have arisen.) What if you came from an egg that started to separate into identical twins but got stuck (or, as the alternative theory has it, were one of two embryos that became fused together) attaching you to your double for a lifetime? As we shall see in these seven cases from the late 19th and early 20th century, nature’s whim can join twins in the strangest of places – from the breastbone to the buttocks – making life difficult, to say the least. Given the state of medical knowledge at the time, surgical separation would have been out of the question in many cases, even if no organs were shared. Here are some of history’s most famous conjoined twins.