Two penniless Americans (Humphrey Bogart and Tim Holt) during the 1920s in Mexico join with an old-timer (Walter Huston, the director's father) to prospect for gold. The old-timer accurately predicts trouble, but is willing to go anyway. The film is fictional, but presents a very realistic scenario: By the 1920s the violence of the Mexican Revolution had largely subsided, although scattered gangs of bandits continued to terrorize the countryside. The newly established post-revolution government relied on the effective, but ruthless, Federal Police, commonly known as the Federales, to patrol remote areas and dispose of the bandits. Foreigners, like the three American prospectors, were at very real risk of being killed by the bandits if their paths crossed. The bandits, likewise, were given little more than a "last cigarette" by the army units after capture, even having to dig their own graves first.
The film shows the Americans doing just about anything for money: drilling oil, digging for gold, begging and more. And once gold comes into the picture, the men who once claimed they were not greedy see things differently. Bogart actually goes mad, after he gets greedy and paranoid... during which he encounters a gila monster! The most memorable scene of this film involves the bandits, who don't need any "stinking badges". While the line is much more quotable in "Blazing Saddles", we couldn't have "Blazing Saddles" (or "UHF") without this film... just about everyone, even those who never saw or heard of "Sierra Madre", knows the badges line.
Humphrey Bogart's best film is probably "Casablanca", but this one features him in a nice, rough exterior. Yes, sometimes leading men have beards and are covered in dirt. Pretty boys do not stay pretty boys after digging in the hills, or at least that wouldn't be realistic. This film does a fine job trying to "keep it real", so we have to commend Huston not only on his directing, but his wonderful location scouting.