Rethymnon (both city and province) was a very important center of Cretan folk music and dance, with some of its vintage recordings from 1920-1955, as well as others from Hania province and city, memorialized in a fabulous collection entitled Protomastores (''first/best masters', roughly).
Although the collection has been reissued on CDs, it originally comprised a box of ten cassettes, accompanied by a book with text about the musicians (with adjacent English translations), photos, and song lyrics (in Greek), as well as an introduction with photos and text about the instruments and drawings illustrating Cretan dance (with English translation). Anyone interested in authentic Cretan folk music should ask for this collection in music stores. You won't get the book, though, with the CD collection.
The city of Rethymnon (population approximately 25,000), despite the increase in tourists during the past 25 years, is still a more provincial and slower-moving place than either of the two big cities in both directions. A long sandy beach flanks the town, with the walls of a massive Venetian fort at one end up above it on the hill, and below it the old Venetian harbor and a lighthouse.
The old parts of town are graced with both Venetian and Turkish buildings, the latter with over-hanging wooden balconies with iron supports, though sometimes it's hard to tell which is which, as generations have restored and added on to the buildings. There are mosques, and Turkish fountains.
The University of Crete has some of its departments in Rethymnon, bringing students from all over Greece to the city, along with the usual ambience of university towns.