A pallet

Did you know that

In Europe, over 25 million cubic metres of timber are used every
year to make pallets.

In Europe over four billion wooden pallets are in circulation at any one time.
This means that 108 billion kgs of CO2 are stored in the form of pallets.

The average lifespan of a timber pallet is between 5 and 7 years.

I didn't!

Oh, and if you come across an old abandoned pallet then you can make a brilliant vertical garden from it. Full instructions here.