John Grierson was a very important person who lived a long time ago and is known for making movies in a special way. He was born in Scotland in 1898 and grew up to be a very smart man. He loved learning new things and started making movies when he was grown up.
Grierson wanted to make movies that were not just for entertainment, but also to teach people about important things like history, science, and the world around them. He called these special movies "documentaries."
Grierson believed that documentaries could be used to make the world a better place by showing people things they didn't know before. He thought that if people were more informed, they could make better decisions and help solve important problems in their communities.
One of Grierson's most famous documentaries is called "Night Mail." This movie tells the story of how letters get delivered from one place to another in England by train. It may not sound very exciting, but it was very important to help people understand the postal system and appreciate the hard work of postal workers.
Overall, John Grierson was a pioneer in the field of documentary filmmaking and helped shape the way we use movies to educate and inform people.