Earhart sent her final radio transmission on July 2, 1937 during a record attempt to fly around the world at the equator.
Earhart and navigator Fred Noonan disappeared in the final minutes of a flight from Lae, New Guinea, to Howland Island in the Pacific.
At 07:42 local time, as she flew toward the target destination, Earhart called the Coast Guard cutter Itasca, stationed at Howland Island for support.
"We must be on you, but cannot see you -- but gas is running low. Have been unable to reach you by radio. We are flying at 1,000 feet," she said.
Earhart's final inflight radio message went out an hour later, at 08:43.
"We are on the line 157 337. We will repeat this message. We will repeat this on 6210 kilocycles. Wait," she said.
What happened after that last radio message remains a mystery.