Conjoined twins: Allison and Amelia
According to the University of Maryland Medical Center, conjoined twins occur about once every 200,000 live births and can be documented back to at least 1100 when two twin girls, Mary and Eliza Chulkhurst from Kent, England, were born joined at the hip. Conjoined twins used to be called Siamese twins because of a famous pair in 1811 named Eng and Chang Bunker from Thailand, which was called Siam at the time, but the term is no longer used.
An X-Ray of Allison and Amelia shows where the twins were joined.Credit: The Children's Hospital of Philadelphia video
