Thomas Dambo routes his daily bike commute past neighborhood dumpsters to find materials for his builds. In the past several years he’s upcycled concert waste into a “Limbo Land” theme park; old wheels, tarp and plywood into a teardrop-style bicycle camper; beer-dispenser tubing into hanging lights; cafeteria food buckets into animal statues, etc.

As a kid Dambo built treehouses and boxcars from scavenged materials because it was all he had access to. Today he still views waste as a very accessible and affordable building material, but he also sees reuse as a moral imperative, albeit a very entertaining one. For his Forgotten Giants series he turned scrap wood into six enormous sculptures hidden in the forest and fields west of Copenhagen as an “open air sculpture treasure hunt”.

Remake Christmas is an annual holiday market made entirely from waste and offering visitors the chance to upcycle their own ornaments and gifts. Happy Swings on the Danish island of Bornholm is an interactive meeting place where people meet for coffee, brainstorming and a swing. For one of his first ideas, “Happy City Birds”, he used container finds to build birdhouses. Since then he’s built more than 3000 and left them hanging in cities around the world.