Will all 7 Millennium Problems be solved by 2040?
Prediction market on manifold. https://www.claymath.org/millennium-problems 1 was solved - the Poincare conjecture - by Grigori Perelman. There are 6 remaining. There are 17ish years left before this market closes.
Liquidity: $1,000. Resolves: 12/31/2039.