Filmed on location in Paris, and based on an Alistair McLean novel, this film involves a wealthy man known simply as "Mr. Smith" who sends a team of experts on to the Eiffel Tower, armed with explosives they plant in various locations. Smith then demands a ransom, threatening to blow up the tower if he doesn't get his money. What Smith does not know is that two of his "experts" are government agents sent to infiltrate his group, and a third is an ex-C.I.A. man. Exciting idea, outstanding stuntwork, and good performances-especially by Keir Dullea and Dame Celia Johnson.