Nenana

The Nenana Ice Classic: a charitable ice pool that has been held annually since 1917. Participants pay a small fee (currently $3.00) to guess the exact date, hour, and minute that the ice on the Tanana River will break up in the spring.

• The Tripod: In early March, a large, black-and-white striped wooden tripod (technically a four-legged "quadpod") is erected on the frozen river.

• The Mechanism: The tripod is connected by a cable to a shore-based clock. When the ice moves downstream exactly 100 feet, the cable pulls a pin, stopping the clock and triggering a siren that alerts the town.

• The Jackpot: What began as a $801 bet among railroad engineers has grown into a massive lottery, with recent jackpots often exceeding $200,000 to $300,000.