What is 'Watchmen' by Alan Moore and Dave Gibbons famous for, and why is it considered a landmark work?

'Watchmen' is renowned for its deconstruction of the superhero genre. It challenges traditional notions of heroism and morality, exploring themes of power, corruption, and societal consequences. Its intricate plot, complex characters, and philosophical depth have earned it critical acclaim and cemented its status as a landmark work in comic book history.