The 3.2-million-year-old fossil known as Lucy is now at the Houston Museum of Natural Science for its first display outside of Ethiopia where it was discovered, and some scientists are raising concerns the rare tour may end in a damaged fossil.
"Lucy is an iconic fossil. She is one of the few fossils that has a name recognized by the public at large," Lehman College anthropology professor Eric Delson told ABC's John Berman.
View images of Lucy and the exhibit here.
Anthropologist Donald Johanson discovered the fossil, which forms 40 percent of a complete skeleton, in 1974. He named it Lucy as the Beatles hit "Lucy in the Sky with Diamonds" was playing at the Ethiopian camp when the set of bones was discovered.
Lucy is about 3 feet 6 inches tall and helped researchers discover that our ancestors walked upright before their brains expanded in size, a discovery that helped reshape scientific views of evolution.
"It's kind of narcissistic, but it's about us," said Dirk Van Tuerenhout, curator of the Houston museum. "We're studying where we come from, and with Lucy, we can really tell the story."
When Lucy was discovered the fossil was considered so delicate that for decades it was kept in a vault in Ethiopia to be seen only by researchers.
Except for two brief displays, the public in Ethiopia was only allowed to see a model.
Looking to bolster the country's image, Ethiopia decided to send Lucy on a six-year tour of the United States along with a set of objects and artifacts that detail the history of the African nation.
"Lucy's Legacy: The Hidden Treasures of Ethiopia" will remain in Houston, its first stop, through next spring.
While it's an incredible opportunity for the American museum-going public to see Lucy, some of the world's leading scientists say taking the fossil on the road is an incredibly bad idea.
The famed paleontologist Richard Leakey told The Associated Press, "It's a form of prostitution … it's a gross exploitation of the ancestors of humanity."
And some museums, including the Smithsonian Institute, refused to house the exhibit.
"All it takes is one problem, and something might be damaged irreparably," Delson said.
Museum officials insist they are taking the greatest care and will fly Lucy in two specially-designed suitcases.
"Miss Lucy traveled in the best conditions -- on Ethiopian Airlines," Van Tuerenhout said.
It's still unclear where else the fossil will be displayed. The tour will be finalized and announced this fall with more U.S. cities to be included.