"[W]hat was mesmerizing... was this... marvel of modern engineering... was going to be the cleanest waste-to-energy power plant in the world. No toxins coming out of the chimney. So we thought maybe a mountain of trash could become an actual mountain. Our nearest ski slope... is 6 hours away in Isaberg... Sweden... We could put 2/3 of Isaberg's main slope on the roof of the power plant, and so we did. ...The kind of cliff face of the mountain is made out of these gigantic folded raw aluminum bricks that are... planters. ...Raw aluminum so they... reflect the surroundings, so... the building changes color over the course of the day. ...The entire power plant is ...daylit. 50% of the facade is transparent. ...This spring it's going to open the tallest in the world, 300 feet. ...[T]he roof is maybe the most exciting facade. ...[T]he skiing is ...free. It's a public park. If you want to use the lift system, you have to buy a lift pass. It's... designed to... help spread vegetation to the surrounding... post-industrial area. You have hiking paths, different... activity zones. You have... vegetation that changes over the... season. There's more than 400 different trees. ...It's purely indigenous species. If Denmark had mountains this is probably what they would look like. ...[T]he entire roof park has been made for a budget of... $13 million dollars... absurdly inexpensive so everything has... been done with... the least... maintenance and... acquisition cost. ...Maybe the most important material, because Denmark doesn't have enough snow so... we found this Italian company that makes this... mat that has the same friction as a groomed slope. The only problem was that it was... ugly. Also because of the and contraction it had to be split in... 7x7 foot squares. So we sat down... with the company and... managed to develop a... new product... by joining every two circles [holes in the material] in two... directions... This... simple geometric invention... now the standard product of the company, meant that we could have a continuous surface on the... roof... We color-coded it so that the brighter the slope... the less likely... to crash... [E]ventually the grass grows through... [T]he grass... holds the mat to the roof, so eventually it's going to be like skiing on an alpine meadow. ...What is amazing ...it ...shows this ...world-changing power of architecture ...[M]y son is ...never going to remember that there was a time when you couldn't ski on the power plant in Copenhagen ...[F]or him and his entire generation, that's going to be their normal ...the starting point from where they start having crazy ideas about their future. ...A landmark for this ...idea of hedonistic sustainability, that a sustainable city can also be, not just better for the environment, but better for the people living there."