The Bilderberg Group is a secret club where important people from different countries go to talk about important things. Think of it like a super top secret club where grown-ups go to talk about things that affect the whole world. The people who go there are called "elites" and they include politicians, businesspeople, and some really smart experts in different fields.
It's called the Bilderberg Group because it started in 1954 in a hotel called the Hotel de Bilderberg in the Netherlands. Since then, they've met every year in secret places. The meetings are not open to the public, so nobody knows exactly what they talk about.
Some people think that they might be up to something fishy, like trying to control the world. Other people think that it's just a normal meeting where important people want to have important conversations. But because it's so secretive, nobody really knows for sure what goes on there.