A metre is a comfortable measurement. The length of a pike is about one metre, that of Finland is a million, and a cubic metre is one thousand litres. A thousand litres of water weighs a tonne. Easy! It must have been a walk in the park to develop and adopt such a simple and functional system. Or was it?
![An open wooden box, inside measurements made of brass.](https://blogs.helsinki.fi/hum-object-of-the-month/files/2021/03/Mittanormaalit.jpg)