Experts say the process requires "two custom fireworks", smoke test rehearsals and Vatican firefighters on standby.

But then three weeks later, the cat — now known as Gertrude — "had a little Wisp.” Wisp, a nearly 10-week-old Persian cat who is known for her unique appearance and chatty personality ...

each part painstakingly designed to ensure that a wisp of smoke carries a clear message. Experts told the BBC that the process requires "two custom fireworks", smoke test rehearsals and Vatican ...