Even though new distros installers tend to support filesystem encryption out of the box, most of the time, it might be interesting to actually understand how it works, mainly when it happens that your system fails to boot :).
Most literature found on the Internet tend to cover how to set up LVM over a partition encrypted with LUKS, this tutorial takes another approach and will explain how to create LUKS encrypted partitions over LVM. The reason for this.... I wanted to have unencrypted partitions :D.