happen upon

Though the creature had already been described by science, researchers lacked significant specimens to inspect until Darwin happened upon a Megatherium skull.

“Just a little further,” I kept telling myself, and then we happened upon it.

Chimps are patriarchal, forming all-male coalitions that patrol their territory; they react violently when they happen upon an outsider or neighboring clan.

No special equipment or ingredients needed, but if you happen upon a bag of Reese’s miniature pretzel cups, my neighbors and I give them our enthusiastic approval.

Dr. Hamilton’s nephew Kevin Lacey said it had not been previously announced because Dr. Hamilton was a private and modest man and was “concerned about what would and would not happen upon his passing.”