This is the URN resolver of The National Library of Finland.

If you want to resolve an URN manually, you can do it by modifying the URL of the page by adding the URN to it. For example, you can add URN:NBN:fi-fe2021080942632, and thus URL would be https://urn.fi/URN:NBN:fi-fe2021080942632.

More information is available in English, Finnish and Swedish.