A massive fire broke out at Rio de Janeiro's Olympic Velodrome, engulfing the roof in flames.
This is the third fire in the last eight years at this stadium.
Emergency services arrived at around 4:17am to find half the roof collapsed. Around 80 firefighters with 20 vehicles battled the blaze, as black smoke blanketed the city.
Rio's fire department stated: "We avoided a major tragedy. The cause is not yet known, only a forensic investigation can determine it. But it is a fact that the fire started from the outside, in the canvas." They explained that the roof was entirely made of synthetic material, which melted, creating a structure similar to a spider's web.
Fortunately, no injuries were reported and the fire is now under control. The cause is being investigated.