Tetsuwan Atom (1980)

Set in a future where machines have advanced to the point of autonomy and become a point of major contention in the political and social realms, Astro Boy (1980) chronicles the struggles of a crime-fighting young robot named Atom. Created in the image of his enigmatic inventor's deceased son, Atom survives rough beginnings, getting saved and adopted by the benevolent Dr. Ochanomizu. In his pursuit of justice, Atom finds himself in the midst of numerous clashes with various factions, and is often faced with the harsh realities of the world.

The original Japanese version of the series ran for 52 episodes while the English version ran for a reduced 51 episodes, as the first two episodes were combined into one, resulting in the omission of the entire backstory of the main antagonist. This creates issues when the antagonist appears later in the series, and the anime refers back to the events which were cut.

(Source: Astro Boy Wiki and Wikipedia)