The problem with making a list of the worst films ever is that there are so many bad films that no one sees, or so few people that even if you find the film, you can't get a consensus on it. That's become much simpler with streaming and video on demand, because even bad movies are available to see. It's also simpler with internet power, because we have film ranking sites that gather opinions from far and wide, like IMDb, Rotten Tomatoes, and CinemaScore. CinamaScore ranks movies by letter grades, taken from polls of people who watched a movie on its opening night. CinemaScore has rated 21 movies that received an aggregate grade of F. Now, when you read the phrase "worst of all time," you have to remember that these are necessarily recent movies because of the way the data is collected. The Wrap lists these movies with a short quip about why they were so bad, but Mental Floss has all the trailers for your viewing pleasure -or displeasure. Of the 21, I have only heard of three of them, and have seen none.