Although the majority of this footage comes from the 1908 Olympic Games, at least one clip predates the 1908 event.
On July 2, 2021, a video started circulating on social media that supposedly showed various athletes competing at the Olympics more than 100 years ago in London, in 1908:
Generally speaking, this video truly comes from the 1908 Olympics, although there's one clip in this montage that predates the 1908 games.
The majority of the footage in the above-displayed clip comes from a video that was shared to the YouTube page of Great Britain's Olympic team in July 2020. That nearly four-minute-long video gives a longer look at the archers, pole vaulters, high jumpers, gymnasts, and runners. It also gives a glimpse at what the shot put, hammer throw, high dive, marathon, and tug-of-war looked like at the 1908 games.
The shorter viral clip does include a few snippets not shown in the 1908 Olympics video above -- mainly, the moment when a bunch of penny-farthing bicycles, a style of bike with one large wheel in the front and a much smaller wheel in the rear, ride around in a circle. This clip appears to come from a different sporting event called the Intercalated Games that was held in Athens in 1906. While these games featured athletes from various countries competing in a wide range of sports, the International Olympic Committee does not consider them an official Olympic event.
Today, the IOC and a few sports historians do not consider the 1906 Intercalated Olympics to be official Olympic Games, although these Games may have helped save the Olympic Movement. After the debacles of 1900 and 1904, the Olympics were in desperate straits. The Greeks had wanted to host more Olympics and they proposed holding “interim” Olympics, every four years in the even year between the Olympics. The first of these was scheduled in 1906.
The circling penny-farthings can be seen at the 3-minute mark of the following video. We're not exactly sure what is happening during this moment. While penny-farthing racing is a real (and somewhat obscure) sport, this appears to either show a clip from the opening ceremony or just a few penny-farthers fart(h)ing around:
https://www.youtube.com/watch?v=YP0rOqe3Js0
The viral Reddit clip features at least one other moment not included in Great Britain's 1908 Olympic compilation: The moment marathon runner Dorando Pietri crosses the finish line. While this truly took place at the 1908 games, it's worth adding a few details.
The Italian runner's performance was interesting to say the least. He started slow, then went really fast until he appeared physically exhausted. During the final stretch of the race, Pietri made a wrong turn and collapsed multiple times. As he was aided by race officials to his feet, he would end up being disqualified from the race.
But immediately it became clear that something was wrong. Dazed, Dorando headed in the wrong direction. Officials directed him in the right direction, but he collapsed. Helped to his feet, he collapsed again…and again and again. Finally another runner, John Hayes of the United States, ran into the stadium. The officials lifted up Dorando and helped him across the finish line. He was disqualified for receiving outside aid, but his plucky effort made him famous.