"Aftera $145 million facelift, Paris' Longchamp Racecoursewill once again host Europe'srichest race, the Prix de l'Arc de Triomphe, Sunday.
The prestigious race has been held at leafy Longchampsince the days of Napoleon IIImore than 150 years ago, and after a two-year residency at Chantilly while its home was redeveloped, it's back.
The winner of the ""Arc"" -- a one-and-a-half-mile test of speed and staminafor three-year-olds and above -- will earn five million euros ($5.7 million), making it the third richest horse race in the worldbehind the Pegasus World Cup and the Dubai World Cup.
Tens of thousands of spectators are expected to attend this weekend's two-day meeting, which commands a total purse of 9.7 million euros ($11.1 million).
READ: Roaring Lion claims victory at Irish Champion Stakes
Based in the wooded Bois de Boulogne area in western Paris,Longchamp closed it gates in October 2015 to undergo its significant upgrade.
The new grandstand offers ""transparent"" views both east and west. On one side, visitors will have 180 degrees of unobstructed views of the racecourse and the Eiffel Tower, and to the west, racegoers can enjoy views of the River Seine.
READ: The white-faced horse who's the talk of the racecourse
The French architect behind the design, Dominique Perrault, writes: ""The main challenge of this project is for it to be able to host the (Prix de l'Arc de Triomphe),which draws up to 60,000 spectators, under exceptional conditions, while also welcoming a much smaller crowd on ordinary racing days.""
errault is also the designer behind the athletes village for the Paris 2024 Summer Olympics as well as the Olympic Tennis Stadium in Madrid which is the home of the Madrid Open.
Two grandstands dating back to the 1960s have been replaced by a single 10,000-seater grandstand at Longchamp.
""The public is always in visual contact and proximity to the horses and professionals, without ever coming into direct contact,"" Perrault says.
With solar panels and heating generated from geothermal energy, the new design is also eco-responsible.
READ: Stradivarius scoops 1.28M in virtuoso season
""It will really be a green bubble for Parisians, just 10 minutes from L'Arc de Triomphe,"" Olivier Delloye, who heads governing body France Galop, told CNN Sport last year.
Perrault says the inclined stand, which slightly overhangs from its base, is inspired by the movement of a galloping horse, and its color scheme is inspired by the reds and golds of autumn leaves in October, its busiest time.
Visitors also have the choice of three dining areas, from fine dining with panoramic views to an affordable garden party-themed restaurant and a French gastronomy brasserie.
With racegoers flooding through Longchamp's gates each October, the remainder of the yearthe stands have previously remained largely empty. Around 30 race meetings are held there annually, attracting just a few thousand spectators each time.
Sotit's hoped that the new grandstand will attract business when racing events aren't being staged.
Currently, the racecourse also doubles as a music festival venuein the summer months, hosting events like Lollapalooza and Solidays.
Despite the major upgrade, the rest of the racecourse, dating back to 1857, remains unchanged.
READ: Superstar mare Winx retains top spot in world rankings
Nonetheless some trainers have voiced concerns about the state of the track following Arc trials earlier in September.
John Gosden, British trainer of defending champion and this year's Arc favorite Enable, told Racing UK that he had ""enormous concern"" about the ground and suggested itmight not have received the attention it should have during the development.
Jockey Frankie Dettorirode Enable to victory in the 2017 Prix de l'Arc de Triomphe at Chantilly.
Enable has also won a string of races including the Cheshire Oaks, Epsom Oaks, Irish Oaks, and the King George VI and Queen Elizabeth Stakes at Ascot.
Visit CNN.com/horseracing for more news and videos
Gosden says the filly's biggest threat will be trainer Williams Haggas' Sea of Class, a winner of the Irish Oaks and Yorkshire Oaks."