Is there a train from Copenhagen to Gothenburg? Why do some say you have to cross the sea, and there's no train, but others say there is a train?

There is indeed a train from Copenhagen to Gothenburg, but it requires passing through the strait between Denmark and Sweden. Therefore, the train will pass through a section of undersea tunnels during its journey, namely the Great Belt Tunnel (Oresund Bridge) in Denmark and the Oresund Tunnel (Oresund Tunnel) in Sweden. That’s why some people say it’s necessary to cross the sea, but in fact the train does exist. Therefore, although there is a saying that there is no train, the actual situation is that there is a train, but it needs to go through the undersea tunnel.