[In 1909, US Navy engineer Robert Peary completed an expedition that he claimed was to the North Pole. Although this is heavily disputed by modern historians, he was credited for the achievement at the time.] The "undiscovered" things are:

• South Pole: Wouldn't be reached until 1911.
• Fountain of Youth - famously searched for by Ponce de Leon
• Lost Lenore: Reference to Edgar Allan Poe. The phrase comes from The Raven, he also wrote the poem Lenore, which doesn't explicitly describe her as "lost", though definitely dead.
• Universal Peace: World Peace has been sought for years, hasn't been achieved yet.
• Captain Kidd's Treasure: Famously lost pirate treasure.
• Something for nothing/Shares: Reference to expression "You can't get something for nothing" Basically, a working get-rich-quick scheme.
• The Great American Novel: One of those things that's always discussed in American literary circles, never had a universally-agreed candidate
• Honest graft: Using one's political power to take advantage of opportunities without corruption. Probably not possible.
• Perpetual motion: The idea that a machine can be built that generates power without cost.
• The Man who wrote Shakespeare: Reference to the conspiracy theory that Shakespeare's works were written by someone other than Shakespeare.
• The Man in the Iron Mask: A prisoner in 17th to early 18th-century France forced to wear an iron mask. Identity unknown.