Amelia Earhart stands in front of the Lockheed Electra she was trying to fly around the world in 1937.

Courtesy NASA 1937: At 8:43 a.m. local time, the Coast Guard cutter Itasca, steaming off Howland Island, receives this faint transmission from Amelia Earhart: "KHAQQ calling Itasca. We must be on you but cannot see you – but gas is running low…."

She vanishes along with her navigator, Fred Noonan, into the Central Pacific, and they're never heard from again.

The disappearance of the celebrated flier remains perhaps the most tantalizing unsolved mystery in aviation history. In the age of Charles Lindbergh and other daredevil fliers, Amelia Earhart became a household name in 1928, after becoming the first woman to fly across the Atlantic. True, it was as a passenger with a male pilot and copilot, but she soloed across the Atlantic in 1932.

Although fellow pilots rated her as no better than competent, Earhart parlayed her sex and her absolute devotion to flying into a celebrity that few of her contemporaries enjoyed. And it's not like she wasn't legit: Earhart was the first pilot of either sex to successfully fly solo from Honolulu to the U.S. mainland, reaching Oakland, California, on Jan. 11, 1935. She wrote voluminously about her experiences and worked hard to promote aviation, both to women and to the public at large.

By 1937, though, the 39-year-old Earhart was weary of both the celebrity and the flying. Saying she had one last good flight in her, she was determined to make it a doozy: She would fly her specially modified Lockheed L-10E Electra completely around the world.

A first attempt, flying westward from Oakland in March, ended either with a blown tire or pilot error as she was taking off from Honolulu. The plane was badly damaged and shipped back to Lockheed in Los Angeles for repairs.

For the second attempt, Earhart was joined by Noonan. They altered the flight plan for an eastward journey to compensate for shifting weather patterns, and left Oakland on May 21. From Miami, their route took them south along the eastern seaboard of South America, then a hop across the Atlantic Narrows to Africa. They skirted the southern coast of Asia, crossing the Indian subcontinent, Southeast Asia and Australia before arriving in Lae, New Guinea, June 29. They had flown roughly 22,000 miles at this stage and had another 7,000 to go, all of it over the Pacific Ocean.

As they left Lae on July 2, the cutter Itasca was already on station off Howland Island, Earhart's next destination, to help guide the plane in. Ship-to-plane radio contact was established, but something – possibly problems with the radio directional finder aboard the Electra – undermined communications.

Whatever the reason, Noonan was unable to pick up the Itasca's homing signals. Itasca even raised steam for a possible visual sighting, but the aviators were unable to locate either the cutter or Howland Island. Seventy-five minutes after receiving Earhart's last transmission, which included the line, "We are on the line 157/337," the Itasca began searching for the plane.

Such was Earhart's stature that President Franklin Roosevelt dispatched nine U.S. Navy ships and 66 aircraft to help in a search that proved fruitless.

Nevertheless, various stations around the Pacific reported receiving unidentified signals, leading to the hope that Earhart and Noonan had somehow managed to find land somewhere. None of these reports amounted to anything.

Over the years the mystery only deepened, leading to some pretty fanciful theories concerning Earhart's fate, including the possibility that she was captured by the Japanese during World War II and forced to broadcast propaganda to American GIs as Tokyo Rose. Iva Toguri and all the others who broadcast as Rose should have been so lucky.

The likeliest explanation for what became of Earhart and Noonan is that they ran out of fuel, ditched at sea and drowned, but there are other theories out there still being pursued. In any case, they were officially declared dead Jan. 5, 1939.

As for Earhart herself, she knew she was taking a big risk for high stakes:

"Please know I am quite aware of the hazards.... I want to do it because I want to do it. Women must try to do things as men have tried. When they fail their failure must be but a challenge to others."

Source: Various

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March 6, 1937: Birth of a Soviet Hero, First Woman Into Space

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May 27, 1937: A Bridge Over the Gate? Are You Crazy?

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