What happened to Alonso's F1 career?
Fernando Alonso was once the most revered driver in F1, but a case of wrong timing and poor luck in recent years has led him to announce his exit. 17 years ago, a teenage Alonso first arrived in F1 with an uncompetitive Minardi at the back of the grid.
Few imagined the backmarker would one day become the driver to end Michael Schumacher and Ferrari's historical run of five successive championships. Alonso did just that in only his fourth season by winning six races on route to his first ever world championship in 2005.
A year later he beat Schumacher in a season-long battle to become the sport's youngest double champion.
But it proved to be the pinnacle of his F1 career.
17 wins and 60 more podiums followed over the next 12 years, but no third title.
So what happened to a career that promised so much?
In this slideshow, we will examine the five key moments that changed things for Alonso.
The start of the decline
Alonso made the dream move to Mclaren for 2007 with a rookie teammate in Lewis Hamilton joining him.
With Schumacher gone, things looked set for Alonso to begin a new era of dominance.
But the Spaniard instead found a new challenger a little too close to home in Hamilton.
The rookie made spectacular progress in no time at all and became the equal of the two-time World Champion.
As the year progressed, tensions within the Mclaren camp reached a boiling point when Alonso blocked Hamilton in the pitlane in Hungary 2007.
Alonso would later fail to defend his title in the final race to Kimi Raikkonen with the Spaniard and Mclaren parting ways after a bitter year.
Returning to Renault, who had fallen down the pecking order in his absence, was the only option left for Alonso to continue for 2008.