In order to have time to enjoy each of them, let's keep to one sequence per day for each user (and I insanely hope we'll have enough people around to avoid two following posts from the same user

Try to find on youtube, dailymotion, and so on, an opening sequence from any kind of movies, you particularly like and explain quickly the reasons why it is so. If you don't manage to post the video properly here, post the link to the page and I or a mod will edit your post.
I starts this topic with the amazing opening sequence of John Woo's 1989 The Killer.

I personally love this sequence as these are in fact the very first minutes I saw from John Woo. When I saw this movie I was actually looking for a movie in English, in order to practice my English for an exam to take place the day after. In France the movie had kept its international title "The Killer" which sounded English so I went in ... Quickly I realized either my English was really bad, either they weren't speaking English

Quickly it didn't matter anyway as the first 5 minutes caught me for a long ride which would make me discover many jewels from Hong-Kong, that movie included.
In this first minutes you get every informations about Chow Yun Fat's character, from its job to its sense of loyalty and its not so cold heart.
Now we are quite used to kick-ass action sequences but in 1989 this opening really rocked and I still find it very efficient today

Don't forget there is a topic about this movie in The Theater by the way, here
