History, strategy, and rain: The conundrum F1 teams face ahead of the Belgian GP

Formula 1 heads to Belgium this weekend for another jaunt around the famous Spa-Francorchamps circuit in the Ardennes Forest of temperamental weather.

The circuit's original triangular design was built in 1921 after designers Jules de Their and Henri Langlois van Ophem penned a 14.9km track on public roads between the towns of Francorchamps, Malmedy, and Stavelot.

The design remained unchanged for nearly six decades, until a redesign in 1979 gave us the circuit we know today.

Small changes occurred since, but Spa-Francorchamps has always remained the longest circuit on the current calendar at 7.004 km.

"The length of the track, with Spa being the longest lap of the year, and the variation in elevation - which is also the biggest of the whole season - means that it's easy to find wet conditions on one part of the track while it's completely dry elsewhere," says Mario Isola, Pirelli's motorsport director.

"But here comes Sebastian Vettel!!!" ??#BelgianGP #Seb5 pic.twitter.com/YzIBLMWmVr

The winners

Though Spa-Francorchamps hosted its first Grand Prix in 1924, it was never part of a world championship. That changed in 1950 when the F1 Championship came into being, and the circuit was one of seven that formed part of the maiden season.

That year, Juan Manuel Fangio became the first driver to take an F1 victory at the 14.9km circuit, with Alfa Romeo teammate Nino Farina in second. Fangio would win two more times around Spa, but Michael Schumacher secured the most wins here - six - albeit on the redesigned track.

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Kimi Raikkonen is widely regarded as the 'King of Spa', even with just four wins here to his name. His performances, especially those at the