There are two main requirements for skiing — mountains and snow. Unless you're at the Copenhill Power Plant Park. Located in the heart of the Danish capital, the urban mountain resort utilizes a waste-to-energy power plant to create a 450-meter long artificial ski slope with four lifts, a slalom course, freestyle park, and zero snow. Instead, visitors can shred a vibrant green surface year-round. The rooftop also offers hiking and running trails along with the world's tallest climbing wall on the side of the building. After a day on the slopes, you can retreat to the cafe at the summit for dinner and drinks.