The Autódromo do Estoril, officially known as Autódromo Fernanda Pires da Silva, is a motorsport race track in Portugal, owned by state-run holding management company Parpública. Its length is 4.182 km (2.599 mi). It was the home of the Formula One Portuguese Grand Prix from 1984 to 1996. The capacity of the motorsport stadium is 45,000. The circuit has FIA Grade 1 license.
The Estoril circuit was built in 1972 on a rocky plateau near the village of Alcabideche, 9 km from the city of Estoril, the beach resort lending its name to the circuit. The course has two hairpin turns, noticeable elevation changes, and a long (986 metre) start/finish straight. Its original perimeter was 4.350 km (2.703 mi), and the maximum gradient is nearly 7%.
Its first years saw many national races, as well as an occasional Formula 2 race. However, the course soon fell into disrepair due to the owning company having been taken over by the state between 1975–78, and a significant redevelopment effort was needed before international motorsport returned in 1984.
Estoril became a popular event on the F1 calendar, the setting for many well-known moments including Niki Lauda winning the 1984 championship, his third and final, from McLaren team mate Alain Prost by just half a point by finishing second to Prost at the 1984 Portuguese Grand Prix. Three times world champion Ayrton Senna's first F1 win in 1985, Nigel Mansell's notorious black flag incident and subsequent collision with Senna in 1989, Jacques Villeneuve's overtaking Michael Schumacher around the outside of the final turn in 1996, and Riccardo Patrese's being launched airborne in a near-backward flip after colliding with Gerhard Berger on the main straight in 1992.
Estoril was dropped from the F1 calendar for the 1997 season, though it continued to play host to top-level single-seater, sports car and touring car events, including the FIA GT Championship, the DTM and the World Series by Renault. A new redesign of the parabolica turn which saw its length reduced to 4.182 km (2.599 mi) was implemented in 2000 in order to obtain FIM homologation.