As the popular television drama series concluded, viewers concocted numerous "LOST" season six theories, many of which attempted to answer lingering questions from the previous seasons.  "LOST" season six concluded the mysterious story of the Oceanic Flight 815 survivors who landed on a strange island.    

The island is not real.  As sideways flashes showed each of the cast members after the flight landed safely in Los Angeles, California, one "LOST" season six theory was that the island never existed and was simply fake.  This sideways universe was first presented in the season six premiere and continued through the series finale.  

The island is real.  Though never fully revealed until the series finale, one "LOST" season six theory believed that the island was in fact real, while the sideways universe was actually fake.  As scenes with each character were presented alongside scenes from the island, viewers were arguably torn over which story line was real and which was not.  

The characters are in purgatory.  Continuing a "LOST" theory first presented in earlier seasons, some alleged that the characters never survived the plane crash and were stuck between heaven and hell.  A "Last Supper" promotional picture for "LOST" season six only reinforced that theory.  

Richard Alpert cannot age.  As revealed in "LOST" season six, episode nine, the island's advisor Richard Alpert, portrayed by Nestor Carbonell, is seen landing on the island in the 1860s.  In modern times, Alpert appears exactly the same, having never aged a day.  This "LOST" season six theory however is proven false when Alpert appears with a gray hair on his head.  

The candidates were pre-selected.  When Ilana Verdansky brings a team to the island and begins to speak about the crash survivors as candidates, one of many "LOST" season six theories explored if the characters were pre-selected to come to the island.  The theory is proven correct when Hurley Reyes takes Jack Shephard to a lighthouse and reveals that island protector Jacob has been watching them for many years.  

The Man in Black cannot be killed.  As many characters unsuccessfully attempt to kill the Man in Black, who took over the body of John Locke, viewers and characters alike began to believe he could not be killed.  This however is proven false when he is killed by Kate Austin after the cork at the heart of the island is removed.  

The Smoke Monster will never be explained.  A mystery of the series from season one, a prominent "LOST" season six theory questioned if viewers would ever learn what the Smoke Monster actually was.  This theory was negated in a final episode of the show when it was revealed that the Smoke Monster was actually Jacob's evil twin brother.  

Charles Widmore will kill the island's inhabitants.  When he arrives on the island vi submarine, one "LOST" season six theory believed all would be killed by Charles Widmore, the original leader of The Others.  While Widmore attempted odd experiments on the island, before he could kill anyone, he was killed himself.  

The entire show was a dream sequence.  A theory during "LOST" for all six seasons, viewers contemplated what would be revealed as the series concluded, especially if the story was real or an elaborate dream sequence.  It was not until the "LOST" series finale that the story was finally explained to be real.  

The island is actually hell.  Thoroughly argued as a "LOST" season six theory, some felt the characters never survived the crash and were sent to the island, which was hell.  The "LOST" series finale disproved this theory when the entire cast reunited in a purgatory state where all remained before moving on to the afterlife together.

-Angela Huetteman