was to be sincere about the christmas story of approximate, but to have him about to new york and jimmy kahnyour dad. >> james kahn, famous for his role in "the godfather." >> bada bing! >> i'm not going to tuck you in. >> all right, let's do this. >> reporter: some of the big names in the movie were unknowns at the time, and then things got physical. it took the art department weeks to build that set. >> we had one take to destroy it. so favreau says just go nuts. >> reporter: as it turns out, this scene and several others were shot at an abandoned psychiatric hospital in vancouver. >> you tend to cameo in them. >> yeah, yeah. >> you play the doctors in this who does the dna test. >> it's fun to be in the movie and see myself. what i'm more proud of is the narwahl that comes up out of the water. that's my voice. bye, buddy, hope you find your dad. what i'm probably remembered the most for. >> reporter: but what most people remember "elf" for is how much they love it. >> it's surprising, how each year it just gets higher and higher on people's list. i wouldn't have predicted that, running ar