During a particularly rowdy night of production, Klaus Kinski, irritated by the noise from a hut where cast and crew were playing cards, repeatedly fired a Winchester rifle into it. One of the bullets took the tip of an unnamed extra's finger off. Werner Herzog immediately confiscated the weapon and it remains his property to this day.
In his commentary, Werner Herzog explained how he manipulated star Klaus Kinski into giving the performance he wanted. Kinski wanted to express Aguirre's madness at the end of the film with very loud shouting. Herzog had him do that for an hour and a half until Kinski grew tired. Then, he was very quiet and much more contained.
Many of the scenes were unrehearsed and unstaged, blurring the line between the cast acting in character and simply reacting to their situations. In one opening scene, when the carriage holding Aguirre's daughter tips over and threatens to collapse, a hand comes in from the right side of the frame to assist the actors in steadying their hold. That hand belongs to director Werner Herzog.
According to Werner Herzog's commentary, he paid the men who were to provide the monkeys at the end of the film only half of what they asked for, thinking they would try to run off with the money. The dealers took the money, then sold the monkeys to someone else, and prepared to fly them to Florida. In desperation, Herzog pretended he was a veterinarian and said the monkeys didn't have their vaccination documents. After filming, he released the monkeys into the wild.
Werner Herzog claims to have written the screenplay in two and a half days. He wrote a good portion of it while traveling with his soccer team, during games and on bus rides. Following one game, the team was very drunk, and the player seated behind Herzog vomited on his typewriter, ruining many pages of the script. Herzog was unable to salvage the pages, and tossed them out the window. He was also unable to recall what he'd written on them.
The film was originally shot in English, the only language the multi-national cast and crew had in common. The original production sound was recorded on location, but not used because of its poor quality. The whole film was later dubbed into German. Werner Herzog claims that Klaus Kinski wanted too much money for the recording sessions, so Gerd Martienzen dubbed him. Even audiences that have seen Kinski's other performances often can't tell the difference.
Werner Herzog and Klaus Kinski had met many years earlier, when the struggling young actor rented a room in Herzog's family's apartment. Kinski's antics during the three months he lived there left a lasting impression. Years later, Herzog knew the volatile actor was the only possible man who could play the mad Aguirre, and sent Kinski a copy of the screenplay. "Between three and four in the morning, the phone rang," Herzog recalled. "It took me at least a couple of minutes before I realized that it was Kinski who was the source of this inarticulate screaming. And after an hour of this, it dawned on me that he found it the most fascinating screenplay and wanted to be Aguirre."
Near the end of the shooting, Werner Herzog thought he'd lost all the negatives. Several weeks later, he discovered that the shipping agency at the Lima airport had completed all paperwork needed to ship the film cans, but hadn't actually shipped them.
According to Werner Herzog, Klaus Kinski threatened to abandon the film entirely at one point during the shooting over Herzog's refusal to fire a sound assistant. Herzog says he threatened to kill Kinski and then turn the gun on himself if Kinski left - and later declared he was quite prepared to do so, knowing that the authorities would write it off as a hunting accident. Kinski stated in interviews that Herzog wielded a pistol to emphasize the threat, but Herzog denies this.
This film, as well as several other early films by Werner Herzog, were shot on a 35mm camera that he stole as a young man from the Munich Film School, a predecessor to today's prestigious film school 'HFF München'. Herzog himself never was a film student there or anywhere. He readily admits to the theft but also justifies it with the significance of the films he's made with the camera and his right to artistic expression: "It was a very simple 35mm camera, one I used on many other films, so I do not consider it a theft. For me, it was truly a necessity. I wanted to make films and needed a camera. I had some sort of natural right to this tool. If you need air to breathe, and you are locked in a room, you have to take a chisel and hammer and break down a wall. It is your absolute right."[Cronin, 2003]
Werner Herzog was attacked by fire ants when he was chopping a tree branch with his machete. He didn't cut it down completely, so the ants poured down on him and bit him "about 150 times". As a result, he got a bad fever.
The finale is significantly different from Werner Herzog's original script. The director recalled, "I only remember that the end of the film was totally different. The end was actually the raft going out into the open ocean and being swept back inland, because for many miles you have a counter-current, the Amazon actually goes backwards. And it was tossed to and fro. And a parrot would scream: "El Dorado, El Dorado"..."
In 1971, while Werner Herzog was location scouting for the film in Peru, his reservation on LANSA Flight 508 was cancelled due to a last-minute change in itinerary. The plane was later struck by lightning and disintegrated, with one person surviving after a free fall. Almost 30 years later, Herzog made Wings of Hope (2000), which explored the story of survivor Juliane Koepcke.
Klaus Kinski's crazed performance bore similarities to the real Aguirre, a "true homicidal megalomaniac". Many of his fellow soldiers considered his actions to be that of a madman. Kinski's use of a limp reflected one that Aguirre actually had, the result of a battle injury. Aguirre's frequent short but impassioned speeches to his men in the film were accurately based on the man's noted "simple but effective rhetorical ability."
The low budget meant the production couldn't afford stuntmen or elaborate special effects. The cast and crew climbed up mountains, hacked through thick jungle, and rode ferocious river rapids on rafts built by natives. At one point, a storm caused a river to flood, covering the sets in several feet of water and destroying all the rafts. The flooding was immediately incorporated into the story, as a sequence including a flood and rebuilding the rafts.
Werner Herzog explained how the choir-like sound was created. "We used a strange instrument, which we called a 'choir-organ.' It has inside it three dozen different tapes running parallel to each other in loops. ... All these tapes are running at the same time, and there is a keyboard on which you can play them like an organ so that [it will] sound just like a human choir but yet, at the same time, very artificial and really quite eerie." The instrument was most likely a Mellotron M400, introduced in 1970. It had 35 keys and was a staple of early-1970s progressive rock.
The trivia items below may give away important plot points.
While plot details and many of the characters come directly from Werner Herzog's imagination, historians have pointed out that the film incorporates some 16th-century events and historical figures fairly accurately. Aguirre, Ursúa, Don Fernando, Inez, and Florés were all involved in a 1560 expedition to find the city of El Dorado. Commissioned by Peru's governor, Ursúa organized a group of 300 men to travel by way of the Amazon River. He was accompanied by his mistress, Doña Inez. Aguirre, a professional soldier, decided that he could use the 300 men to overthrow the Spanish government in Peru. Aguirre had Ursúa murdered and proclaimed Fernando "The Prince of Peru." Fernando was eventually murdered when he questioned Aguirre's scheme of sailing to the Atlantic, conquering Panama, crossing the isthmus and invading Peru. Others who attempted to rebel against Aguirre were also killed. The surviving soldiers conquered Isla Margarita, off the coast of present-day Venezuela, and made preparations to attack the mainland. By then, Spanish authorities had learned of Aguirre's plans. When the rebels arrived in Venezuela, government agents offered full pardons to Aguirre's men. All of them accepted. Aguirre murdered his daughter Florés just before his arrest. He was captured and dismembered. Herzog's screenplay merged the 1560 expedition with the events of an earlier Amazon journey. In 1541, Gonzalo Pizarro and his men entered the Amazon basin in search of El Dorado. Various troubles afflicted the expedition. Sure that El Dorado was very close, Pizarro set up a smaller group led by Francisco de Orellana to break off from the main force, forge ahead, and return with news of what they had found. The group traveled down the river on a brigantine. Gaspar de Carvajal, a Spanish Dominican friar, kept a journal of the expedition. The historic Gaspar de Carvajal (1500-1584) had settled in Peru and dedicated himself to the conversion of indigenous Perivuans.
The screenplay was shot as written, with some minor differences. In an early scene, Pizarro instructs Ursúa to lead the scouting team down the river. In the script, Pizarro mentions that in the course of the expedition Ursúa could possibly discover what happened to Francisco de Orellana's expedition, which had vanished without a trace several years earlier. Later in the screenplay, Aguirre and his men find a boat and the long-dead remains of Orellana's soldiers. Further down the river, they discover another ship lodged in some tree tops. In the screenplay, Aguirre and others explore the boat but find no sign of Orellana or his men. Werner Herzog ultimately eliminated references to Orellana's expedition. The sequence with the boat caught in a tree remains, but seems to be a hallucination.