I gotta give major props to the WB animation wiki for this entry as I had never even heard of the 1998 animated series Histeria! I guess the show's mission was to educate kids about history while entertaining them and so episodes featured historical figures from Teddy Roosevelt to Billy the Kid to Leonardo da Vinci. But tucked away in several episodes were DC comics Easter eggs. The first such egg occurred in the episode featuring inventors. After Alexander Graham Bell invented the telephone booth, Superman, er, Fuperman wasted no time using the compartment to change into costume.
The series' William Clark (of Lewis and Clark) bore a striking resemblance to WB's own animated Clark Kent.
The Übermensch appropriately appeared a third time with philosopher Frederich Nietchze who coined the term "Superman."
The Caped Crusader was not to be forgotten with his merchandise being featured prominently in the episode Americana.
And the Boy Wonder would even got his moment along side heroic "Renaissance Man" Leo da Vinci.