The Nenana Ice Classic began in 1917 when Alaska Railroad surveyors pooled $800 and bet on when the ice would disintegrate on the frozen Tanana River. Today the gambling contest is still being held only the stakes are higher with a jackpot usually exceeding $300,000. A tripod is set up after the Tanana freezes and in the spring any surge of ice will dislodge it, the exact time of the occurrence determining the winner. Ice Classic tickets are on sale throughout Alaska from February 1 to April 5 and during the summer in Nenana.