Set over 20 years prior to the main One Piece story, this limited release OVA chronicles the confrontation between Gold Lion Shiki and Gold Roger as well as other events around the world around the time of the Pirate King's execution.
9Anime is the best site to watch One Piece Film: Strong World Episode 0
SUB online, or you can even watch One Piece Film: Strong World Episode 0
DUB in HD quality. You can also find Toei Animation
anime on 9Anime website.