Set deep in the Amazonian rainforests of South America in the mid-16th Century, Werner Herzog's Aguirre, The Wrath Of God is a mesmerizing tale of an adventurer's descent into his own "heart of darkness" and the fate of those he pulls along with him.
Fresh from his conquest of the Incas, Gonzalo Pizarro (Allejandro Repulles) leads his army down the Andes and into the jungle, searching for the legendary city of gold, El Dorado.
The film opens with a languid scene of Pizarro's forces, with their cannons, Indian slaves and supplies, snaking down the mountain side and this quickly establishes the pace that Herzog adopts for this movie.
After a while hacking through the jungle, Pizzaro calls a halt to his expedition and decides to send off a small unit to scout ahead and hopefully learn the location of El Dorado and the disposition of hostile natives in the area.
Leading the group are Don Pedro de Ursúa (Ruy Guerra) - who has brought his mistress along with him, Inez de Atienza (Helena Rojo) - Lope de Aguirre (Klaus Kinsi) - who is accompanied by his 15-year-old daughter, Florés (Cecilia Rivera - and, representing Spanish royalty, nobleman Don Fernando de Guzmán (Peter Berling).
The group heads off on rafts down the river and it's not long before it becomes clear that the already slightly unbalanced Aguirre is determined to undermine his commander, Don Pedro, and take control of the group.
However, he's a canny old sod and orchestrates events so that although Don Pedro is usurped, Don Fernando is put in charge and the group declares itself independent of Spain with Don Fernando as the first emperor of El Dorado.
From there, the film is a series of random encounters as the group drifts down river, plagued by diminishing supplies and harassed by (mostly) unseen natives who pepper them with darts, arrows and spears.
For a film about conquistadors there is little to no actual fighting, although a lot of guns and cannons are fired, because Aguirre's party seldom meets face-to-face any of the people they are trying to conquer and convert to Christianity.
As their adventure continues and the group gets whittled down, so Aguirre's insanity increases and he starts making increasingly bizarre proclamations, as their progress becomes more and more dream-like.
Many, many scenes go on for just a bit too long, just enough time for the audience's mind to start questioning 'what's going on? why am I watching this?'
And the reason you stay watching Aguirre, The Wrath Of God is that it is incredibly compelling.
Filmed entirely on location in the Peruvian rainforest, on tributaries of the Amazon River, there is an almost documentary-like quality to the film's reality.
This is further heightened by Kinski's understated portrayal of Aguirre, a man of incredible charisma and intelligence who is also clearly several cards short of a full deck.
Although far from a silent movie, much emphasis is placed upon silence and the measured dialogue manages to embrace such topics as power, religion, corruption, megalomania and hallucination.
There are obvious comparisons to Apocalypse Now (which was based, in part, on this movie, as well as Joseph Conrad's Heart Of Darkness), both on screen and in the tales of behind-the-scenes antics getting the movie made, although Aguirre relies more on atmosphere and less on an enigmatic protagonist - in a sense Kinski is both Martin Sheen's and Marlon Brando's characters, as both the explorer and the person driven insane by what he finds.
This certainly isn't a film for a casual viewer or those who need "all-action, all-the-time", but as a fictionalised account of how such an expedition, led by a powerful figure such as Aguirre, could go so inevitably wrong, then this is interesting viewing.