20 Things You Didn't Know About From Russia With Love (1963)
11. Uncooperative Rats
The famous Basilica Cistern beneath Istanbul is revealed not only to be an ancient reservoir that is used by Kerim Bey to aid his spying activities, but also to be alive with rats.
When Double-0 Seven and Kerim set off a tear gas bomb to clear the Russian Consulate so that Bond can recover the Lektor decoding device and help Tatiana Romanova to defect, the force of the explosion sends the rats residing in the cisterns into a panic. They swarm towards Bond, Tania, and Kerim, forcing them to find an alternative way out of the subterranean waterways.
The filmmakers attempted to film this sequence at Pinewood Studios, firstly using lab rats coated with cocoa to resemble sewer rats, but the lab rats simply sat and licked the cocoa off of themselves. Alternative rats were sourced, but would not run anywhere until Sean Connery opened the soundstage door.
As it was illegal to use wild rats in British film productions, Terence Young led a small crew out to Madrid, Spain where a local rat catcher helped them to film 200 swarming sewer rats.