I have been to a handful of amusement parks in my time, and to be honest, Linnanmäki (aka Borgbacken) is not the best of the best. But what it does have going for it is that visitors can enter without having to pay an entrance fee. Then, they can choose to purchase a full-day wristband, or buy rides individually.
I ended up visiting Linnanmäki after hanging out in the adjoining Alppipuisto Park. My companions and I had the idea to go up in the Panorama Tower, which is free to visit. As the name suggests, it gives riders a 360-degree view of the city from above. We also then opted to try out the Vuoristorata rollercoaster, which is the most iconic ride in the park. Although it wasn't the best wooden rollercoaster I have been on (the Giant Dipper is perhaps my favorite), it still is quite cool. Fun fact: it was the last rollercoaster in the world to be built with side friction technology.
All in all, I think Linnanmäki knows what it's doing with allowing anyone to enter, because that means people will buy one-off ride tickets, food, etc. If you are in Helsinki for a few days and nearby, consider checking it out and, at the very least, taking a ride up in the tower. read more