Linnanmäki is the most beloved amusement park in Finland and has the widest selection of rides in the Nordic countries. Helsinki's most entertaining district offers also top-quality food and program for all tastes. Linnanmäki is easy to reach from the centre of Helsinki. The admission to the amusement park is free of charge. There are plenty of rides available for children free of charge including the Panorama tower.
https://www.visitfinland.com/mystay/product/linnanmaeki-amusement-park/48355/