All the way at the top higher point of Thessaloniki are ancient walls from the Byzantine Empire. It's worth it to take a cheap tour bus and head up to the top, then walk down back to the main part of the city.
This taverna isn't anything special. We just loved the decor with the vines and ivy. I have a special place in my heart for these Mediterranean kinds of patios, cafes, gardens, etc. Anyplace you can relax with a frappe or a good meal while watching the world stop for a moment.