According to Eli Wallach, when it came time to blow up the bridge, Sergio Leone asked the Spanish army captain in charge to trigger the fuse, as a sign of gratitude for the army's collaboration. They agreed to blow up the bridge when Leone gave the signal "Vai!" (Go!) over the walkie-talkie. Unfortunately, another crew member spoke on the same channel, saying the words "vai, vai!", meaning "it's OK, proceed" to a second crew member. The captain heard this signal, thought it was for him and blew the bridge; unfortunately, no cameras were running at the time. Leone was so upset that he fired the crewman, who promptly fled from the set in his car. The captain was so sorry for what happened that he proposed to Leone that the army would rebuild the bridge to blow it up again, with one condition: that the fired crewman be re-hired. Leone agreed, the crewman was forgiven, the bridge was rebuilt and the scene was successfully shot.
In addition to the train scene,Eli Wallach cheated death in the first scene where Eastwood's character shoots him down from a hanging. The gunshot scared the horse, which took off running at full speed for nearly a mile. Wallach's hands were tied behind his back, and he had to hang for dear life with his knees.
In the scene where the bridge is blown up, and Tuco and Blondie are hunkered down behind sandbags waiting for the explosion, Clint Eastwood's career came within 2 feet of ending prematurely. A fist-sized piece of rock shrapnel from the explosion slams into the sandbag right next to Eastwood's head (watch it in slow motion to see the rock flying in).
During the scene right before the final duel where Tuco (Eli Wallach) is running frantically through the cemetery, a dog can be seen running on-screen at the beginning of the scene. In reality, that was improvised on the spot. Sergio Leone, who was afraid that the scene was going to slip into melodrama, released the dog without informing Eli Wallach first - thus, his look of surprise is quite genuine.
The three man gunfight scene is called either a "Mexican standoff" or a truel (game theory). There are several mathematical papers covering the many complex outcomes of a truel. Other movies that use a truel are Reservoir Dogs (1992) and Pulp Fiction (1994).
Eli Wallach was almost poisoned on the set after drinking acid used to burn the bags filled with gold coin to make them rip open easier when struck with the spade. The acid had been poured into a lemon soda bottle and Wallach didn't know it. He drank a lot of milk and filmed the scene with a mouth full of sores.
The three principal actors are the only ones who speak actual English in the film: Clint Eastwood, Lee Van Cleef, Eli Wallach, with the exceptions of Al Mulock (the one-armed man) and John Bartha (the sheriff). Everyone else in the film is really speaking their native language, mostly Italian and Spanish, and was later dubbed into English.
Eli Wallach remembered that when he first came to Madrid all the hotels were full. Clint Eastwood invited him to sleep over at a friend's house and they shared the same bed. Wallach's wife Anne Jackson told him he could boast that he was the only man to sleep with Clint Eastwood.
After Eli Wallach agreed with Sergio Leone that Tuco would carry his pistol on a lanyard, the director asked him to grasp the gun by shaking his neck, thus making the gun land in his hand. Wallach claimed that he wasn't able to do the intended action, and asked Leone to demonstrate it. When Leone tried, the pistol missed the director's hand and hit his crotch. Leone then told Wallach to hold the gun in the belt.
In the theatrical trailer, Angel Eyes is "The Ugly" and Tuco "The Bad," which is the reverse of their designations in the actual film. This is because the Italian title translated into English is actually The Good, the Ugly, the Bad, not The Good, the Bad and the Ugly, and the Italian trailer had "The Ugly" and "The Bad" in that order. When the trailer was transferred to English, The Ugly and The Bad were not reversed to coincide with the altered title, causing the incorrect designations.
Sad Hill Cemetery was a very-convincing set piece constructed by the pyrotechnic crew and not a real cemetery. Today the site is marked as a local point of interest. Though the central stone 'proscenium' and parapet are gone, the circles of grave-mounds are still quite prominent.
The grips on Clint Eastwood's pistol have an inlaid silver rattlesnake. His pistol in For a Few Dollars More (1965) had the same grips. In the TV series Rawhide (1959), Rowdy Yates (Eastwood) kills a gunfighter carrying a pistol with the same grips and takes it for his own. Eastwood's character would carry the pistol with the rattlesnake grips for the remainder of the series' run.
Four scenes were cut from the original English-language release and were never dubbed into English from Italian. When American Movie Classics showed the "Extended English Version", the scenes were restored. Clint Eastwood and Eli Wallach dubbed their voices for the movie, but another actor had to be found to dub Angel Eyes' lines, as Lee Van Cleef had died in 1989.
Charles Bronson was offered both the roles of Tuco and Angel Eyes (the latter because Sergio Leone feared that audiences would not take kindly to Lee Van Cleef going from the fatherly, likable Col. Mortimer to a sneering villain. He declined both.
The film was shot with a process called Techniscope. This process means that you can shoot without an anamorphic lens, and only use half as much film as you would normally use. The Techniscope process places two widescreen frames on a single 35 mm frame.
Though no specific year or date is stated in the movie, at least part of it takes place during the New Mexico Campaign of 1862. This is confirmed when both the hotel-keeper and Tuco mentions the retreating Confederate General Sibley (the historical Henry H. Sibley) and the advancing Union Colonel Canby (another historical person, Edward Canby). This is consistent with the campaign that took place between Feb-April 1862 in New Mexico and what was then Confederate Arizona.
When Blondie and Angel Eyes are traveling to the cemetery, Blondie shoots a skulker, then counts the number of people that will be traveling together. He says, "Six. A perfect number." In mathematics, a number is perfect if the sum of its factors (excluding itself) equals itself. Six is a perfect number because 1, 2, and 3 are factors and 1 + 2 + 3 = 6. (The next perfect number is 28.)
The prison camp "Betterville" was inspired by the actual Confederate prison camp of Andersonville, where thousands of Union prisoners died, and based on steel engravings of Andersonville from August 1864.
Leone originally titled his story "The Magnificent Rogues" and "The Two Magnificent Tramps," but impulsively changed it during a meeting in which he was pitching the story to United Artists executives Arnold Picker and Arthur Krim. The improvised new title amused them both, and they agreed to put between $1.2 and $1.6 million to make it and retain North American distribution rights.
The trim on Confederate soldiers' uniforms identified the type of unit they were assigned to. Blue indicated infantry, gold cavalry and red artillery. Most of the soldiers in the prison camp wore historically accurate uniforms.
Tuco tells his brother Father Pablo Ramirez (played by Luigi Pistilli) "Where we came from, if one did not want to die of poverty, one became a priest or a bandit!". Ironically, in For a Few Dollars More (1965), Pistilli played a bandit, so in a sense, he's been both a priest and a bandit at the same time.
Eli Wallach claims that Sergio Leone decided that Tuco would carry his pistol on a lanyard and stuck in his belt rather than a holster because Wallach told him he always had trouble putting a pistol in a holster without looking at it.
The train features an armed car with a mortar type cannon. These were actually mounted on trains during the Civil War, especially where railroads had to operate near places where there was heavy fighting.
The following guns are used in this movie. 1.Blondie uses: A Colt 1851 cartridge conversion revolver (with silver snake grips), and a Winchester 1866 "yellow boy" with ladder elevated sights. 2. Tuco uses: A Colt 1851 Navy cartridge conversion revolver with a lanyard. 3. Angel Eyes uses: A Remington 1858 Army percussion revolver. 4. Soldiers used: Gatling guns with drum magazines, and Howitzer cannons.
In the scene where Blondie brings a tied-up Tuco into town to claim the bounty on him, Tuco spits out a cigar and yells out something in Spanish. Translated to English, he is yelling out "Son of a bitch that gave birth to you!"
The bridge that Tuco and Blondie blow was an actual bridge built by Spanish army engineers. The Spanish agreed to blow the bridge only if their captain could be the one to do it. When it came to blowing the bridge the captain didn't notify Sergio Leone and just blew the bridge up without any cameras rolling. The army was so sorry with what they did that they rebuilt the bridge only to blow it up again.
After the scene where Blondie splashes water in Tuco's face in the infirmary, there is a fade-out to the next scene. This was where the intermission was located, but this fade-out was excised in the 179-minute extended version.
In two of the deleted scenes featuring Lee Van Cleef's character, a substitute voice actor - Simon Prescott, was used for the dubbing. Van Cleef had died in 1989, and the scenes had never been dubbed into English.
The trivia items below may give away important plot points.
Mario Brega appears in all 3 of the Dollars Trilogy movies as a henchman for the main villain(s), and in all 3 movies, his character meets an unfortunate demise (oddly enough, none of these deaths is caused by gunfire). In this movie, his character of Wallace is killed when Tuco (chained to him) jumps off the train with him, and bangs his head against some rocks. This is the only movie from the trilogy in which Brega plays an American, whereas in the other movies, he plays a Mexican.
Despite being frequently referred to as a sequel to For a Few Dollars More (1965) ("For a Few Dollars More"), this film is set during the American Civil War whereas that one takes place afterwards, and while Lee Van Cleef here plays a villain who gets killed, he turns up there as a very much alive good guy.