Inception
This is probably one of the most talked about films in recent times, due to how ambiguous the ending was. The entire film about dreams within dreams is such a great concept and this is easily one of Nolan’s best films (though I’m partial to Insomnia as my all time fav).
The famous ending has DiCaprio’s Cobb spinning his totem which never falls in his dreams, and going to play with his kids. We see the top continue to spin, and start to wobble, but never fall. So is he dreaming? Is it real? Was the top really his totem – Nolan will never tell.