Best way to encrypt a partition?

Ok, so I'm wondering... what is the best way to encrypt a partition?

I know that Bitlocker exists, but I am unsure if that is the most secure encryption method for a partition. I want the one that is the most secure.

The method should work with [Windows, Linux], this way I can view the backups on any computer I'm using.

I'm wondering in terms of most secure encryption for a drive partition.