The TT Circuit Assen is a motorsport race track built in 1955 and located in Assen, Netherlands. Host of the Dutch TT race, it is considered "The Cathedral" of motorcycling by the fans. It has a capacity of 100,000 spectators, including 60,000 seats. Since 1992 it is also part of the Superbike World Championship calendar.
The original Assen track was first used for the 1925 Dutch TT (Tourist Trophy) race, held on country roads through the villages of Borger, Schoonloo and Grolloo, and organized by the Motorclub Assen en Omstreken. The brick-paved track had a length of 17.75 miles (28.57 km). The winner was Piet van Wijngaarden on a 500 cc Norton with an average speed of 91.4 kilometers per hour (56.8 mph).