Which was the world's first purpose-built motor racing circuit?

Brooklands was a 2.75-mile (4.43 km) motor racing circuit and aerodrome built near Weybridge in Surrey, England, United Kingdom. It opened in 1907 and was the world's first purpose-built motor racing circuit as well as one of Britain's first airfields, which also became Britain's largest aircraft manufacturing centre by 1918.

The circuit hosted its last race in 1939 and today part of it forms the Brooklands Museum, a major aviation and motoring museum, as well as a venue for vintage car, motorcycle and other transport-related events.

The Brooklands motor circuit was the brainchild of Hugh F. Locke King, and was the first purpose-built banked motor race circuit in the world. Following the Motor Car Act 1903, Britain was subject to a blanket 20 mph (32 km/h) speed limit on public roads: at a time when nearly 50% of the world's new cars were produced in France, there was concern that Britain's infant auto-industry would be hampered by the inability to undertake sustained high speed testing.

Requirements of speed and spectator visibility led to the Brooklands track being built as a 100 ft (30 m) wide, 2.75 miles (4.43 km) long, banked oval. The banking was nearly 30 feet (9 m) high in places. In addition to the oval, a bisecting "Finishing Straight" was built, increasing the track length to 3.25 miles (5.23 km), of which 1.25 miles (2.01 km) was banked. It could host up to 287,000 spectators in its heyday.