In Blade Runner, the dying replicant Roy Batty introspectively says the phrase, during a rain downpour, moments before his own death:
I've seen things you people wouldn't believe. Attack ships on fire off the shoulder of Orion. I watched c-beams glitter in the dark near the Tannhauser Gate. All those moments will be lost in time, like tears in rain. [pause] Time to die.
In the Channel 4 documentary On the Edge of Blade Runner, Rutger Hauer, director Ridley Scott, and screenwriter David Peoples asserted that Hauer wrote the "Tears in Rain" speech. There were earlier versions of the speech in Peoples's draft screenplays; one included the sentence "I rode on the back decks of a blinker and watched c-beams glitter in the dark, near the Tannhauser Gate." In his autobiography, Rutger Hauer said he merely cut the original scripted speech by several lines, adding only "All those moments will be lost in time, like tears in rain", although the original script, displayed during the documentary, before Rutger Hauer's rewrite, does not mention "Tannhauser Gate":
I've known adventures, seen places you people will never see, I've been Offworld and back... frontiers! I've stood on the back deck of a blinker bound for the Plutition Camps with sweat in my eyes watching the stars fight on the shoulder of Orion...I've felt wind in my hair, riding test boats off the black galaxies and seen an attack fleet burn like a match and disappear. I've seen it, felt it...!
Hauer described this as "opera talk" and "hi-tech speech" with no bearing on the rest of the film, so he "put a knife in it" the night before filming, without Ridley's knowledge. --Wiki