How to embed existing website in my Drupal 8 site? I have a site I created with Drupal 8, lets say http://falzon.xyz/.
Elsewhere, I have a site created with Jekyll, a bunch of static pages linked to each other visible http://www.elina-noe.eu/).
I'd like to "embed" the static site as a "subsite" of falzon.xyz, i.e. accessible as http://falzon.xyz/elina-noe/, by 'simply' putting all its files in a subfolder of the D8 site.
How can I do that?
Creating a subfolder inside your docroot folder such as docroot/elina-noe should suffice.  

Put all the subsite files into this folder and if there is a index.html you can access your subsite just by visiting the subfolder http://falzon.xyz/elina-noe/