Roman Polanski had intended to take on the role of the young hitchhiker himself, but Jerzy Bossak, head of the Polish film unit KAMERA (under whose auspices the film was made), turned him down because he didn't consider the director attractive enough. The character's voice, however, is Polanski's, who later dubbed the part over. Zygmunt Malanowicz had a strong, developed, bass voice, which was quite inappropriate for the character.
After the movie became known in US, Polanski was given a proposal to remake the film in English with some known Hollywood actors (rumors talk about Spencer Tracy and Elizabeth Taylor), but he turned it down as he didn't want to "repeat himself".
Initially, Polanski wanted to make a criminal story about a couple which takes a young hitchhiker to a boat trip, and at the end the boy dies in mysterious circumstances. In his version the trip was about a week long and involved some other characters. It was Jerzy Skolimowski who proposed to shorten it to one day and limit the number of characters. The final script was created in only three, four days by Polanski, Skolimowski and Jakub Goldberg in Polanski's apartment. While writing the script they were playing the dialogue, changing the roles all the time.
The first scene in the film shows Andrzej and Krystyna driving a car. As shooting from the platform in front of the car was not yet available, the crew was tied to the car, standing on its mask. To get the proper light effects, they held a blanket with a small hole for the camera. Leon Niemczyk (Andrzej) was really driving this car quite fast (this was crucial to this scene), but he couldn't see anything. He drove the car using the tops of the trees to imagine where the road is.
Forms part of a loose trilogy of films based around a psychological ménage-à-trois with Cul-De-Sac (1966) and Death and the Maiden (1994). All three films feature a couple whose lives are turned upside down by an outside character.
This was Roman Polanski's directorial debut, and the only film he ever made in his native Poland. Shortly after the film was released, Polanski emigrated to France (then to England, and then to the US), where he established his international fame.
The boat used in the movie is rumored to be a former property of Hermann Goering, the Nazi party member and a friend of Adolf Hitler, who used to spend summer holidays in the palace in Sztynort neighboring the filming locations. Sunk during World War II in the Mazurian Lakes, it was restored and is - up to present date - owned by Almatur Travel Agency located in Gizycko, Poland, very popular in Polish showbiz-related circles. The real name of the boat is "Rekin" ("The Shark").
The couple's car, seen in the opening and closing sequences, was initially supposed to be a Mercedes, but this was replaced with a Peugeot during filming to avoid political controversy. (The more expensive car was perceived as an icon of Western luxury and decadence). During the shots, a prominent party member arrived at the plan in the newest model of Mercedes. He was invited by the whole crew with peals of laughter.
The cover of Time Magazine's Sept. 20, 1963 edition used a still from this film. The cover story was about international cinema. The cover photo's caption simply said "LOVERS IN POLISH FILM" without identifying the movie or the actors in the photo.
The trivia item below may give away important plot points.
During one of top mast shots, the cameramen Jerzy Lipman was tied to the mast and held a camera. Although the wind was not strong, the mast swung and the camera was heavy, so it was very difficult to take a good shot. All the time the director Roman Polanski was very excited about the shot and kept asking how it was going. Lipman got very angry and said "Fuck! It is fucking beautiful!" and... dropped the camera to the water. He had forgotten to attach it with the safety cable. The Arriflex camera couldn't be found by the divers and still lies somewhere in the lake.