Oh man...
I don't have the heart to rank em so I'll list a few off.
Except for Helsinki of course which I'm fully certain is the greatest city in the world. Great coffee, friendly people, good food, good transport, walkable, an incredible airport, cute streets, these lovely little upmarket corner shops (R-Kioski? they're everywhere in that part of the world and the feeling they give me just warms my heart so much) and of course one of the best rollercoasters in the world smack dab in the middle of it, what isn't there to love? I love the vibe, I love everything about this place.
Just a ferry ride away from Helsinki is Tallinn, Estonia, a city I purely visited for the +1 completed country on coastercount but fell in love with the old town and it's glorious majestic buildings and lovely tram network. I'd love to spend longer here but alas I was only there for a few hours.
I love most German cities but a few come to mind especially, most notable Nuremberg for its old school German architecture and charming little streets. I was lucky to come during a festival of some kind, so the atmosphere around the place was absolutely full of charm. Visited the oldest sausage restaurant in the world and was treated to some of the best food I've ever had.
Berlin is also great but less for old school charm reasons and more because it's such a culturally diverse place with incredible food everywhere and some interesting history. I only spent a few hours walking around the place but it was such an interesting few hours walking around and taking in the atmosphere I loved it.
All 3 Danish cities I've visited were absolutely brilliant but due to not spending much time in Aalborg or Copenhagen, despite how pretty they are haven't really got a good feel for them. Aarhus on the other hand is fully alive with energy and I was shocked how much of a hive of activity the place is. Copenhagen is also pretty incredible but I spent my whole day there at Tivoli Gardens so I can't comment too much on it other than how great the airport is.
Stockholm is a gorgeous city with lovely cute streets, a FANTASTIC metro where all the stations are like some sort of art showcase, rivers running through the place and rollercoasters, very important.
Sticking with the theme Oslo is also quite an incredible place with a lovely waterfront setting, some of the coolest modern buildings ever, great food and the cutest little hot dog shack somewhere north hole in the wall sort of thing that does the most amazing hot dogs they're so so so good I would be lying if I said Storm: The Dragon Legend isn't my only draw to come back to this amazing place, I would get on a flight purely for those hot dogs I swear!
Quite an underrated city in my opinion is Dunkirk, France. I've often heard it regarded as quite an ugly place but I've travelled through Dunkirk a few times now and love it's setting on the sea, history, cute surrounding seaside villages (Bray-Dunes) and most importantly of all its free to use bus network that just so happens to cross the border into Belgium into the nearby De Panne where you can ride one of the best coasters on the planet...
Paris also gets a bad rep and I can't see why. Cute streets, great cafes, great metro system, friendly staff and some of the coolest landmarks ever. Also Jardin d'Acclimation is such a cute little city park that just so happens to have rollercoasters in it, huge dub.
Rome is the most recent city I've visited and I fell IN LOVE with how many huge cool structures there are, the amount of history here is absolutely insane and I couldn't believe how large the landmarks are in person. The public transport isn't great but some of the greatest food in the world, best cafes, friendliest people and also very walkable. However, I think I actually prefer Verona as a city. It's cute, small, walkable, the streets are imo prettier, the river running through it provides some incredible views, it's a lot more digestable imo and the nearby Lake Garda is incredibly pretty.
I'm sure Salzburg would be on this list for setting alone but given that I spent not even an hour in the city proper I'm going to have to credit Vienna for it's cute streets, museums, great food, rollercoasters (duh), history and metro. However, I've found the people here to be somewhat cold and unfriendly, shame because I really do like the city.
Krakow is incredible. I originally didn't think much of it leaving the central station but upon stepping into the old town my mind changed. What a lovely, charming place. I visited while the Christmas market was on and the vibe was absolutely astounding! So excited to hopefully come back here at some point.
Bruges is another city that leaves much to be desired stepping out of the train station but once you make it into the city proper, it's incredible. Huge old buildings, very cute streets and lots of rivers running through. I've been here a few times now as a transportation hub between Plopsaland De Panne and the UK via Flixbus and I always look forward to my evenings here after a day riding into happiness.
I've often heard American cities aren't great but I fell in love with Sandusky which is apparently a city. Not only is Cedar Point visible across the lake, but the lake has these incredible old timey docks full of cute cafes and restaurants and is lovely and walkable and well taken care of and very old timey and so so so charming. Love the place.
I think I love Pittsburgh more though. It feels like a mix of the best of American cities, with the really awesome huge buildings and parks and cafes and cool restaurants and diners and all that but also European cities with good transportation and pedestrian infrastructure! The bus network here is so good, frequent, clean, there's a rail system that seems nice, and these really cool funicular railways that give you insane views of the city and all its bridges. Such a ridiculously cool place that oozes charm.
I'm actually writing this on a bus right now so I'll add some cities I want to talk more about here but don't have time to; I'll probably continue writing this post one day with details about the following cities that I also adore:
Dublin
Derry/Londonderry
Cardiff
York
Tampere