Now obviously they are two different movies so not everything is the same but the plot structure is the same exact thing. After the heroes have been separated from each other, they reunite at a city, and lead the city's police officers against an army of foes that overpower them. The climax of that battle is one of the heroes, in both cases the billionaire with fancy gadgets flies away with a nuclear bomb in a suicide mission to get enough distance between the bomb and the city but the hero still ultimately survives. The similarities make me wonder that if Nolan saw the Avengers he thought " Crap, it's the same ending"

Also both Black Widow and Catwoman, who are athletic, acrobatic woman,who are expert at seducing, and wear skin tight black outfits ride a fancy motorcycle.