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.
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".
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.
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.
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.