Captain America wears a costume that bears an American flag motif, and is armed with a nearly indestructible shield that he throws at foes. The character is usually depicted as the alter ego of Steve Rogers, a frail young man enhanced to the peak of human perfection by an experimental serum to aid the United States government's imminent efforts in World War II. Near the end of the war, he was trapped in ice and survived insuspended animation until he was revived in the present day. Although Captain America often struggles to maintain his ideals as a man out of his time with its modern realities, he remains a highly respected figure in his community which includes becoming the long-time leader of the Avengers.
Captain America was the first Marvel Comics character to have appeared in media outside comics with the release of the 1944 movie serial, Captain America. Since then, the character has been featured in other films and television series, more recently in the Marvel Cinematic Universe (MCU) portrayed by Chris Evans in Captain America: The First Avenger, The Avengers, Captain America: The Winter Soldier, Avengers: Age of Ultron, Captain America: Civil War, and the upcoming Avengers: Infinity War (2018/2019).
An American billionaire playboy, business magnate, and ingenious engineer, Tony Stark suffers a severe chest injury during a kidnapping in which his captors attempt to force him to build a weapon of mass destruction. He instead creates a powered suit of armor to save his life and escape captivity. Later, Stark augments his suit with weapons and other technological devices he designed through his company, Stark Industries. He uses the suit and successive versions to protect the world as Iron Man, while at first concealing his true identity. Initially, Iron Man was a vehicle for Stan Lee to explore Cold War themes, particularly the role of American technology and business in the fight against communism. Subsequent re-imaginings of Iron Man have transitioned from Cold War themes to contemporary concerns, such as corporate crime and terrorism.
Throughout most of the character's publication history, Iron Man has been a founding member of the superhero team the Avengers and has been featured in several incarnations of his own various comic book series. Iron Man has been adapted for several animated TV shows and films. The character is portrayed by Robert Downey Jr. in the live action film Iron Man (2008), which was a critical and box office success. Downey, who received much acclaim for his performance, reprised the role in a cameo in The Incredible Hulk (2008), two Iron Man sequels Iron Man 2 (2010) and Iron Man 3 (2013), The Avengers (2012) and Avengers: Age of Ultron (2015), Captain America: Civil War (2016), and will do so again in Spider-Man: Homecoming (2017) and both parts of Avengers: Infinity War (2018/2019) in the Marvel Cinematic Universe.