The story about the flag raising being posed was true. It was started, ironically, by Joe Rosenthal. He did not know he had taken the famous photograph until he returned to the States. He did, however, take a second photograph of the five Marines and one Navy Corpsman gathered around the flag. When people asked if he had posed the photograph, he, thinking they were referring to the second photograph said "Of course". It was only after seeing the first photograph that he realized they were referring to that photograph and not the second one.
Clint Eastwood chose to film a large part of this movie in Iceland because the black sand on its beaches closely resembled Iwo Jima.
At the Cannes Film Festival, filmmaker Spike Lee criticized producer and director Clint Eastwood for not displaying African-American Marines who had fought on Iwo Jima. Eastwood's response was that the movie was about the marines who raised the flag on Mount Suribachi. He went on to explain that although African-Americans did fight on Iwo Jima (some can be seen during the briefing scene), the Marine Corps was segregated during World War II, and none of the men who raised the flag were black. Eastwood finally told Lee to "shut his face". Through the media, Lee responded that Eastwood was being an angry old man. Lee was filming Miracle at St. Anna (2008) at the time, a movie about four black soldiers fighting World War II in Italy.
Clint Eastwood would deliberately not tell his actors where all of the special effects were rigged to explode in order to perfectly capture their looks of surprise. This was done with the actors' safety firmly in mind.
Both flags (from the first and second flag-raisings) are now located in the National Museum of the Marine Corps in Quantico, Virginia.