140km, twice up Box Hill, a peloton of just 67 women with teams of a maximum of four riders each: the women's Olympic Road Race will be a difficult one to predict. Cyclingnews has picked five main prospects for the gold medal from the pack.
Marianne Vos (Netherlands)
The women's Olympic road race has one main favourite: Marianne Vos, the woman who has only increased her dominance since she won the road world championship in her first senior year. But in recent years she has come agonizingly short on repeating that accomplishment - she was second place five years in a row after her victory. She also missed out in the last Games in Beijing, coming sixth.
Vos is a favourite in every race she enters: she's won world titles in cyclo-cross, track and the road, and owns an Olympic gold medal from Beijing in the points race in addition to her other 200+ career victories. She can sprint against the specialists and win, she can ascend with the quickest climbers and crush them on descents. She can solo away, out-smart groups big and small and also sacrifice herself for her teammates.
The Netherlands will field an impressive four-rider team: Vos is joined by her trade teammate Annemiek van Vleuten, herself the World Cup winner in 2011, Dutch time trial champion Eleonora van Dijk and Omloop Het Nieuwsblad winner Loes Gunnewijk. They have ample firepower to support Vos in any situation.
Ina-Yoko Teutenberg (Germany)
One of the most experienced riders in the peloton, Teutenberg, 37, is also one of the fastest, savviest and most powerful riders out there. She has shown that she can hold her own on the climbs by winning the women's Tour of Flanders in 2009, so Box Hill should not prove to be an obstacle for the German. She has made improvements in her time trialing, as evidenced by her bronze in the German championships and a 10th place finish at the Worlds in 2011.
London will be Teutenberg's last chance at an Olympic medal, and earlier this year she expressed her desire to win both the Olympic road race and a world championship, two honours surprisingly missing from her vast palmares (168 wins and counting), before retiring. However, any one of her German teammates can also win a medal: Judith Arndt, Trixi Worrack or Claudia Hausler.
Giorgia Bronzini (Italy)
The reigning world champion has had the curse of the rainbow jersey this season, suffering several crashes and injuries, but if history is any indicator we can never count out the Italian team, and certainly not Bronzini.
At 28, she is at the top of her form and took back-to-back wins in the world championship road race in addition to her two titles on the track. Her experience on the road and the track and the support of a strong team with Tatiana Guderzo, Noemi Cantele and Monia Baccaille give Bronzini an excellent chance for a medal, if not the gold.
Emma Johansson (Sweden)
Johansson, 28, is the bridesmaid of the women's peloton - nearly always in contention for the victory but more often landing on the second or third step of the podium. She's taken out ample victories, certainly - they include stages of the Giro Donne, numerous Swedish championships, the overall Tour de Free State in South Africa this year, and the Ronde van Drenthe World Cup - but in the last Olympic Games in Beijing, she took silver to Great Britain's Nicole Cooke.
Can Johansson finally get one major victory? Her team is not the powerhouse like Germany, Italy, Great Britain, the Netherlands or USA, but her timing is uncanny, she is an expert at reading a race and knowing when to mark a move and when to conserve her strength. Expect to see her play off the other strong riders, and with the help of Emilia Fahlin and Isabelle Soderberg, be in the winning move with a firm chance at the podium.
Elizabeth Armitstead (Great Britain)
If any team is under pressure, it will be the British squad, who is looking to maximize their number of gold medals on their home soil. The defending Olympic champion Nicole Cooke has not shown the same spark that propelled her to the Olympic and world titles in 2008, Emma Pooley has declared that the course does not suit her and it is clear by the inclusion of dedicated lead-out rider Lucy Martin in the team that the British are focussed on Armitstead and a sprint finish.
Just 23, Armitstead had a string of good results on the track before deciding to give sole focus to the road following the shift of the Olympic programme. Her sole victory this year at the UCI level was in a minor Dutch race, the Omloop van het Hageland, added to a win in the debut women's Gent-Wevelgem. Yet one cannot discount David Brailsford and his genius at producing medals, and if any of the British women will stand on the podium on Sunday, it will be Armitstead.