Topical jokes are always a risky area of humour. Chances are you are always going to upset someone in your audience. There was a minor furore in France last week with the publication of an advertisement for Courrier International, which suggested that the 9/11 attacks on the Twin Towers in 2001 could have been avoided, had the towers been lower in height. 

The punchline is the message: "Learn to anticipate". 

Funny? Well technically yes, as a joke it works. As a subject matter, the event is probably too recent in the public consciousness. Had the same joke been applied to the Titanic or the Hindenberg, the poster would probably have passed without comment.