Alfred Hitchcock's The Birds is, for me, the ultimate animals-on-the-rampage movie.
Loosely based on Daphne Du Maurier's 1952 novella of the same name, Hitchcock's 1963 masterpiece, brilliantly depicts the sheer tension and horror of what might happen if birds, suddenly and inexplicably, started attacking humans.
It also makes you ponder on just how people would react in the face of such a massive disaster - like a mass bird attack - suddenly hitting their hitherto normal, everyday lives.
A good analogy here would be that of the way hundreds of people from all backgrounds banded together and supported each other, with remarkable and courage and determination, during the blitz of World War II.
Indeed, Hitchcock himself lived through the horrors of the German bombings, and it has been said that his experiences here contributed towards his visualisation for the screenplay of The Birds, as he wanted to convey, as profoundly as possible, just how ordinary people would react and behave in the face of such a terrifying disruption to their lives.
There are so many layers in The Birds that make it such a much-loved, timeless classic, and the sort of film you can watch again and again.
It's not just the mass bird attacks that make it so entertaining; it's other things like the interaction of the characters.
Although the title puts the birds in the forefront, the human relationships are especially emphasised.
Because Hitchcock offers no rational explanation for the bird attacks, he focuses our attention on how people respond in such a stressful situation.
For instance, there's the initially edgy contact between Mitch (Rod Taylor) and Melanie (Tippi Hedren) when he visits the pet shop in search of some lovebirds (and lovebirds, despite that initial edgy exchange, are exactly what Mitch and Melanie become as the film progresses).
There is also the anxious possessiveness of Mitch's widowed mother, who takes a very dim view of any new girlfriend entering her son's life, perceiving her as a potential threat to their mother-and-son closeness.
In addition to these character layers and foibles, you also have many memorable scenes, which add even more power to the entertainment value of The Birds.
For instance, who can forget the sheer nail-biting suspense of the scene where Melanie is sitting on the bench in the schoolyard, smoking and lost in her own thoughts, while just behind her, on the jungle gym, and unbeknownst to her, crows start to amass on the climbing frames.
The sequence is made even creepier by the bizarre nursery rhyme the school kids are chanting in the background.
And when she finally notices them all perched there, like some devilish black hoard poised to strike - and strike is exactly what they do - well, you really feel the intense and terror etched on her face.
This sequence is probably the most famous of all in The Birds, and rightly so too.
It's such a well-crafted masterpiece of sheer, mounting suspense.
Then there is the long discussion scene in the Tides Restaurant, where the staff and customers - including Melanie - try to rationalise why the birds are attacking.
The stuffy, no-nonsense female ornithologist enhances this scene wonderfully, as she expresses her stern incredulity that the birds are really behaving as unusually as the people claim they are.
I could go on about all the different aspects that combine to make The Birds such a brilliant movie.
Although its animals-on-the-rampage theme may have inspired a lot of similar films like Jaws and The Deadly Bees, the sheer magic of Hitchcock's ornithological masterpiece has, for me, never been bettered, and probably never will.