International Bureau of Weights and Measures

The International Bureau of Weights and Measures (BIPM) is like a big library for numbers and measurements. It is like the "official keeper" of measurements like seconds, meters, and kilograms. All the measurements in the world would be different if the BIPM didn't make sure they are the same everywhere. This is important so that when you get something from a different country, like a toy or food, it is the same size and weight as something you would get at home.