Mysteries

• Introduced in Pilot - Part 1

Flight 815 was a regular, timetabled flight from Sydney Airport to LAX. Flight 815 split into three parts in midair due to a sudden loss of structural integrity. The central fuselage landed on the southern coast of the island. 50 people survived the crash, including one yet unborn baby The tail section landed in the ocean on the opposite, northern, side of the island from the center section, about "an hour's run" away from The Other's Village. This third section had 22 survivors.

• Introduced in Pilot - Part 1

The monster is an inhabitant of the island that uproots trees and appears to kill the Pilot in "Pilot - Part 1". In "The 23rd Psalm" its appearance, a cloud of moving black smoke, is revealed. Eko is later killed by the monster in "The Cost of Living".

• Introduced in Pilot - Part 2

Three known Polar Bears are inhabitants of the island, one was shot by Sawyer, another stabbed by Michael, and the third burnt by Locke. Tom mentions to Sawyer that bears were previously housed in the Hydra Station's animal cages.

• Introduced in Walkabout

Dr. Christian Shephard is the father of Jack Shephard and Claire Littleton, and passed away due to a heart attack before Jack and Claire boarded Oceanic Flight 815. After days of not getting rest, Jack began to see hallucinations of his father on the island, it was following these hallucinations that eventually led him to the caves, and a fresh supply of water.

• Introduced in Walkabout

John Locke has previously been paralyzed from the waist down for 4 years and had to use a wheelchair to get around as a result of his attempted murder by his father . After the crash of Oceanic Flight 815, Locke arrived on the island, with his paralysis cured. Locke could once again walk.

• Introduced in House of the Rising Sun

Inside the caves, Jack and Kate find a pair of dead bodies, one a woman, the other a man. They appear to have been in the caves for an estimated 40-50 years. When Jack inspected the bodies, he discovered two stones, one white, the other black, and both appearing to be be highly polished.

• Introduced in The Moth

Not so much a mystery but an ongoing joke. The characters of Scott and Steve are often mistaken for one another. Even after the death of the character of Steve, they continued to claim Scott had perished. It continues to appear in many episodes.

• Introduced in Solitary

The wire on the beach is very mysterious in nature, as it was buried under sand and proceeds in two opposite directions; one way out to sea, and the other way into the jungle.

• Introduced in Solitary

"The Others" is the nickname for the people who appeared to have been born or lived on the island before Desmond, Kelvin, Rousseau and the passengers of Oceanic Flight 815. The two camps had infiltrators attempt to enter the survivor's camps. The Fuselage survivors have encountered Ethan Rom and Benjamin Linus, and the Tail Section survivors encountered Goodwin.

• Introduced in Solitary

The Whispers are voices heard in the jungle. It is unknown who is whispering or clearly known that exactly it is they are saying, or whom they are speaking to.

• Introduced in Numbers

The Numbers were broadcast from the Island's radio transmitter, and it was this message that drew Rousseau's expedition there. Although she later changes the message after the deaths of the rest of her team, the digits had also been heard by other people, eventually making their way to Hurley, who used them to win a lottery. After those around him suffer a series of misfortunes, he begins to believe the numbers are cursed.

• Introduced in Do No Harm

After Sarah was rushed to the ER after colliding with Adam Rutherford in a car accident, she was saved by Jack and put into ICU. Jack informed her that her back was broken and that he was going to attempt surgery, but that possible surgery put the likeliness that she would retain and mobility below the waist extremely unlikely. Jack performed the surgery, which was successful.

• Introduced in Exodus - Part 1

The bird appeared before Jack, Kate, Locke, and Hurley while they were traveling through "The Dark Territory". It lets out a screech that sounds almost as if it is saying "Hurley!" The bird was spotted again when Jack, Kate, Sawyer, Hurley, and Michael were walking through the jungle toward the Others' camp.

• Introduced in Exodus - Part 1

The Black Rock was a ship that had crashed onto the island in approximately 1881. It was found peculiarly in the middle of the jungle in the “Dark Territory”, with no sign or indication of how it arrived there.

• Introduced in Man of Science, Man of Faith

The Department of Heuristics And Research on Material Applications or "The DHARMA Initiative" was created in 1970 by Gerald and Karen DeGroot, and was funded by Alvar Hanso and his Hanso foundation. The sole purpose of the Initiative was to create a scientific way to change the values of The Valenzetti Equation and save humanity. Several DHARMA Initiative bunkers were constructed on the island and discovered by the Flight 815 survivors.

• Introduced in Adrift

The shark which terrorized Michael and Sawyer while they were adrift at sea after their attack from "The Others". The shark was eventually shot by Michael and was killed. The shark bore a logo on its side reminiscent of that used by The DHARMA Initiative.

• Introduced in Orientation

The Hanso Foundation is an organization established by Alvar Hanso sometime in the 1960s. The Foundation was the primary funder for the DHARMA Initiative which would help further scientific research in many fields. The Hanso Foundation funded the DHARMA Initiative and their name appears in the copyrights for the DHARMA Orientation films.

• Introduced in What Kate Did

Kate sees this horse on the island while picking fruit on the island, she walks up to see the horse and it retreats back into the jungle. She later sees the horse in the jungle a second time this time in the presence of Sawyer who also sees the horse. It is highly reminiscent of the one from her flashback which aided her escape.

• Introduced in What Kate Did

The blast doors within Station 3: The Swan that, when lowered, seal the interior of the hatch off from the outside world. A map was drawn by Kelvin and Radzinsky in invisible ink that lists various facts and locations around the island.

• Introduced in The 23rd Psalm

Yemi was the younger brother of Eko, and served as a Roman Catholic priest in Nigeria. After Yemi's death, he later appeared as a vision on the island that his brother crashed on.

• Introduced in One of Them

The hieroglyphics are included in the series of event which make up the apparent end result of what occurs when the button in the hatch is not pushed in the time allotted.

• Introduced in The Whole Truth

When Sun realizes that she is pregnant, and is shocked to hear this as she was told by her doctor in Korea that Jin was incapable of having children. Sun assured Jin that she had never been with another man, and Jin was convinced that the event was a miracle.

• Introduced in Lockdown

The cache of food and supplies attached to a parachute found in the jungle by Jack and Kate. The survivors of flight 815 later collected the food inside, and kept it on what Bernard described as a "kitchen on the beach".

• Introduced in Dave

Dave was an imaginary friend of Hurley's from the Santa Rosa Mental Health Institute who later showed up on the island.

• Introduced in S.O.S.

Flashbacks in S.O.S. show that Rose was diagnosed with an unidentified terminal illness and had only a year to live. Rose believes that her terminal illness has gone into remission because of the island.

• Introduced in Live Together, Die Alone

The broken statue was discovered by the Sayid, Jin, and Sun while sailing on the Elizabeth. The statue is of a four-toed left foot which is wearing a sandal. It is unknown if this statue originally was part of a larger colossal statue or whether it was purely built solely as a foot, or if it is in fact a ruse used by "the Others".

• Introduced in The Cost of Living

When Locke, Sayid, Desmond, Nikki, and Paulo were exploring the Pearl Station, the group stumbles upon a monitor that is connected to another station. A man with an eye patch, wearing a DHARMA jumpsuit, steps into the picture and looks directly into the camera before severing the connection.

• Introduced in Par Avion

The Sonar Fence surrounds the Barracks and blocks any attempt to pass through them. If an individual makes an attempt to enter through the field a sonic wave is emitted which results in the individual suffering a cerebral hemorrhage.