The Coca-Cola 600, originally the World 600, is an annual 600-mile (970 km) NASCAR Cup Series points race held at the Charlotte Motor Speedway in Concord, North Carolina, on the fourth or last Sunday of May and during Memorial Day weekend. It is the longest race on NASCAR's schedule. It is unique for having track conditions that change throughout the race due to the race having a day to night transition. The race starts around 6 p.m. when the track is bathed in sunlight for about the first third of the race. Roughly the second third happens at dusk, and about the final third of the race occurs at night under the lights.