PARIS LA DEFENSE ARENA was transformed from a rugby stadium into a state-of-the-art swimming venue in just 36 days.
The modern 30,680-seat stadium has been hosting Adam Peaty and Co in the Paris 2024 Olympics' swimming events.
Opened in 2017, it is usually home to rugby side Racing 92.
Being a multi-purpose indoor arena, however, La Defense has hosted plenty of other events.
These have included several high-profile concerts - with Taylor Swift playing there back in May.
Ahead of this summer's Games, the venue underwent a drastic change.
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Its rugby pitch was removed, replaced by two 50-metre pools - one used for competition and the other reserved for practise.
In amazing timelapse footage, incredible major changes can be seen taking place.
Despite the impressive turnaround, the arena's competition pool has caused controversy.
With times down in a number of events, questions have been raised by legends of the sport.
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Two-time medallist Nick Gillingham asked on social media: "Did pool maintenance do a back wash down the pool to speed the water up and slow down the swimmers for this race?"
Ordinarily, despite a minimum depth of two metres, Olympic pools are typically three metres deep - as that is the requirement for synchronised swimming events.
But with Paris' new Aquatics Centre hosting the synchronised events this time around, La Defense Arena's pool is only two metres and 15 centimetres deep.
It has been hypothesised that the greater "turbulence" caused by water rippling back off the walls is what's causing slower times.
In Paris La Defense Arena on Sunday night, Team GB legend Peaty achieved a silver medal - despite testing positive for Covid just hours later.
The 29-year-old will not have to isolate and could return to action in the team events later in the Games.