When I grew up here in Sweden, milk came in these containers:

en.wikipedia.org/wiki/Tetra_Brik

The design of milk packaging is quite interesting;

kommerduihag.se/kommer-du-ihag-hur-mjolkpaket-sag…

15 years or so ago the Brik was changed to this:

www.arla.se/artiklar/var-vanligaste-forpackning/

It was apparently done for two reasons:

1. EU regulations started requiring that milk packages were sold in resealable containers.
2. Customers had requested the same to enable storing the packages lying down.

A smaller version of the tetrahedron style package is still in use for coffee milk.