We spent a weekend in Copenhagen where we got to know that you can easily go to Sweden by train over the oresund bridge. If you get the chance to visit one more country in such a short time - of course you do it.
Starting either from the main station in Copenhagen or from the airport you go roughly half an hour to Sweden with that train (costs around 30€ per round trip).

You cannot buy the round trip at once, you need to purchase the ticket to Sweden in Denmark and the ticket back to Copenhagen in Sweden. But that's easy - you just use the ticket machine at the main station and there you go.

The train drive was awesome. That view s amazing and probably better than the fact that your in Sweden in just a few minutes!
You go over the oresund bridge that is at some points up to 60 meters high.
After about half an hour you arrive in Malmö, a southern Swedish city.
There we just walked around into a park and into the central point where you can have a nice coffee. Malmö is pretty quiet and not really touristic but that's fine since we just spent a few hours there.

As a local I use the bridge regularly both by train and by car and it works all the time well and it is still an engineering marvel and still very well maintained.

The Oresund Bridge is unusual but not exciting, but still requires a look if possible. We were lucky to drive over it or should that be under. Yes while you start off driving over the Oresund bridge but then you find yourself in a tunnel and then on the artificial island of Peberholmen. All up it was a total length of 15.9 km. That's what I call amazing.