Bard College is known for its Classics program. Somewhere on the Web there is a video clip transferred from film of 1930s students in ancient Greek costumes having an Olympic-style competition on the fieldhouse.
This graphic series from Bard attempts to show the stages of a typical Greek sacrifice of a sheep, but it suffers from a degree of prettiness. For instance:
Scene 14: the improbable fire. No ash buildup, and no one gets smoke in their eyes later
Scene 16: Half-raw, half-charred sheep heart. . . yum!
Scene 17: Where did the fire go? Who stripped the bones, and how long did that take? There is archaeological evidence for the burning of bones. Does everyone else stand around getting hungry? One source I read suggested that the meat was often boiled (plain or with onions?); another says that priests (or their agents) could sell their portion of the meat in the marketplace.
Scene 19: That must be wine with a very high alcoholic content!
Still the basics are there. By comparison, Muslims seem not necessarily to bother with altars for their animal sacrifices.
Christianity, too, grew up in a culture, temple Judaism, that practiced sacrifice, as did surrounding cultures. The idea of Jesus-as-sacrifice must have carried a lot of emotional impact then based on what people had seen for themselves, as opposed to being just a dead metaphor as it is now.
It's like "flip side" from phonograph albums or all the steam-power metaphors still in our language: "get fired up," "build up a head of steam." When did you last fire a steam boiler?
When I was a child, I was just grossed out by phrases like "washed in the blood of the Lamb." All bloody--yuck! At least if I had seen blood-splashed altars, it would have meant something to me.
Sometimes the only way to learn is to do it. An essay in The Pagan Book of Living and Dying describes the outdoor cremation of a corpse on a Texas ranch. The deceased friends' had the land, the firewood (old corral rails), and the inclination, and it was what he had wanted. So they build a pyre around the corpse and lit it . . . and then had to wait, because a body in a wood fire does not burn instantly. What to do? They had food, drink, and time--so they played games: volleyball or whatever, just like at a picnic. Of course! You always read about "the funeral games" at the burial of some ancient hero.