A cradle is rocked in the wind, high in a treetop, until the bough gives way and cradle, baby and all come tumbling down. It reads gentler than it sounds on the page, since the swaying rhythm of the lines is built for rocking a real child rather than alarming one. One of the best-known lullabies in English, sung long before it was ever written down.
From Mother Goose / Nursery Rhymes (traditional). See the whole collection.
Hush-a-bye, baby, on the tree top!
When the wind blows the cradle will rock;
When the bough breaks the cradle will fall;
Down will come baby, bough, cradle and all.
Public domain. Text from The Real Mother Goose (Blanche Fisher Wright, 1916), via Project Gutenberg. View the source edition