The City Night Line service between Amsterdam and Copenhagen takes place aboard the Borealis sleeper train. A restaurant car serves passengers between Hamburg and Copenhagen. There are two border crossing points at Emmerich and Flensburg.
Roskilde is a Danish city on the island of Zealand. Its train station is a major stop en route between Copenhagen and the rest of the country, as well as for international routes.
The city has held a music festival in the city since 1971. The Roskilde Festival is one of the largest European music festivals, with all profits donated to charity.
If you plan to travel between Copenhagen, Hamburg, Frankfurt and/or Basel, there is a City Night Line overnight sleeper train service called Aurora that runs daily. Other sleeper services are available to Amsterdam.