The most Romantic city in Greece
Visiting Thessaloniki you have many opportunities to compare the sea and montain,best month for visiting is September. You have to visit Kastra , at the top of the city, also the traditional Greek taverns at Ladadika. You can find lots of museams at the center of the city. Dont forget to visit the White Tower (Lefkos Pirgos )
Also on September you can visit the International Exibition with so many participations of other countries.
Taste Ouzo and special sea food at Krini and karampournaki , also Perea near the sea
We dont Metro yet but its romantic walk the city :-)