Rare and valuable bits of history that predate Iowa becoming a state by thousands of years are going on display this week at the State Historical Museum in Des Moines. While they look like long-tusked hairy elephants, museum curator Bill Johnson says two woolly mammoths are the centerpieces of the museum’s largest-ever exhibit, opening Saturday.The first mammoth was found in 2001 when the hole for a parking ramp was being dug in downtown Des Moines, some 55-feet down. It’s thought to be 16-thousand-500 years old. The second mammoth is from Wisconsin and shows butchering marks, stone tools and a crushed skull — evidence it was taken down by ancient people at a time when the glaciers were receding. Johnson says it’s unclear if the Des Moines mammoth was also killed by early Iowa hunters. He says the bones were chewed up by an auger, so they can’t tell if there were any kill marks on the animal.Opening of the exhibit will coincide with lectures, video presentations, dancing, story-telling, stone-tool demonstrations and a giant ice castle, in keeping with the ice age theme. The Wisconsin mammoth is fully reconstructed and stands 12-feet high and 20-feet long. Johnson explains why it’s important that Iowans learn about the mammoth and this period of time.He says this beast was the last of the great “ice age” beasts and it was walking the Raccoon River valley at about the same time humans first entered Iowa. It was a time of great change as the region was shifting from the ice age, or glacial period, to the time of human occupation. For more information, surf to “www.iowahistory.org” or call (515) 281-4011.