Many Nursery Rhymes have darker origins. Ring around the Rosy as it is more commonly known here in the USA is a great example. In the version most known here in the South/West USA the words are:
Ring around the Rosy
A pocketful of posies
Ashes, Ashes
We all fall down
North/ East USA and Europe more commonly sing
Ring a Ring o'rosies
A pocket full of posies
A-tishoo, A-tishoo
We all fall down
This historical rhyme dates back to approximately the Great Plague/Black Plague of London in 1665 (bubonic plague) The symptoms of the plague included a rosy red rash in the shape of a ring on the skin (Ring around the rosy). Pockets and pouches were filled with sweet smelling herbs ( or posies) which were carried due to the belief that the disease was transmitted by bad smells. The term "Ashes Ashes" refers to the cremation of the dead. The English version of "Ring around the rosy" replaces Ashes with (A-tishoo, A-tishoo) as violent sneezing was another symptom of the disease.