Tens of thousands of people from nearly every nation on earth have descended on Copenhagen this month for the UN climate summit. As the delegates try to piece together a framework for reducing greenhouse gas emissions, they’re also absorbing lessons from one of the world’s leading cities in sustainable transportation. In Copenhagen, fully 37 percent of commute trips are made by bike, and mode share among city residents alone is even higher.

Copenhagen wasn’t always such a bicycling haven. It took many years of investment in bike infrastructure to reclaim streets from more polluting, less sustainable modes. Last week, I was able to squeeze in a whirlwind tour with Mikael Colville-Andersen, the bike culture evangelist behind Copenhagenize and Copenhagen Cycle Chic, to get a taste of the city’s impressive bike network and cycling amenities. Watch this video and see how Copenhageners flock to the streets by bike even in December, when average temperatures hover just above freezing.