Stepping into a series with around 1,000 episodes is overwhelming, but One Piece is worth it. It isn't really regarded as the best anime of all time for absolutely nothing. One particular Piece features a few of the most intricate, complex environment-developing and ideal storytelling in anime.
2021 update: I've been around the fence here about deleting this since it's so improperly published, I used to be seventeen at enough time of creating and not a local speaker, and my impression on a single piece and anime generally has changed considerably to the worse.