5 of the wildest conspiracy theories behind Amelia Earhart's disappearance

• Amelia Earhart was one of the most famous aviators in the world when she vanished in 1937.
• Her disappearance remains one of the greatest unsolved mysteries of all time.
• From her being a spy to her having lived in New Jersey under an assumed identity, many conspiracy theories surround her disappearance.

Amelia Earhart was the first female to fly across the Atlantic.

However, 81 years ago the American aviatrix vanished over the Pacific Ocean during an attempt to circumnavigate the globe by plane. To this day, the mystery behind her disappearance remains unsolved.

Here's what we know: on July 2, 1937, Earhart and her navigator, Fred Noonan, departed from Lae, New Guinea. They were heading for Howland Island, a small island located in the central Pacific Ocean, but they never arrived. By 1939, both Earhart and Noonan were declared dead.

While the case remains unsolved, conspiracy theories abound over the late pilot's fate. Here are five of the most compelling guesses behind what happened to them.

1. Earhart crashed her plane and drowned in the Pacific Ocean.

Crash-and-sink theorists postulate that Earhart ran out of fuel while trying to locate tiny Howard Island, and subsequently crashed into the open ocean and drowned.

This theory is supported by the fact that Earhart and Noonan put in a number of calls to the US Coast Guard ship "Itasca," communicating that they were low on fuel and having trouble finding Howard Island.

Despite the $4 million rescue authorized by President Franklin D. Roosevelt to find the pilots, no trace of the aircraft, Earhart, or Noonan was ever found.

2. She landed safely — but on the wrong island.

We know that Earhart was aware that she was running low on fuel, which means one of two things — she either crashed somewhere, or landed successfully.

One theory suggests that Earhart managed to land her aircraft safely — just not on Howard Island, as anticipated. The International Historic Aircraft Recovery Group believe that Earhart ultimately landed on Gardner Island, a nearby deserted island that is now called Nikumaroro, when she couldn't locate Howard, and then perished as a castaway.

However, since her aircraft was never found this remains nothing but a theory.

3. She was captured and taken prisoner by the Japanese.

Last year a photo was discovered in the National Archives that depicts a woman who resembles Earhart sitting on a dock in the Marshall Islands near a man who resembles her navigator, Noonan.

The discovery of the photograph helps substantiate the theory that Earhart and Noonan didn't crash at all, but instead landed in the Marshall Islands, where they were taken prisoner by the Japanese.

Per INSIDER, retired government investigator Les Kinney told NBC News that the photo "clearly indicates that Earhart was captured by the Japanese," despite Japanese authorities' insistence that they have no record of Earhart ever being in their custody.