Nijmegen
Don't let the whimsical Dutch architecture and cobblestone streets fool you: Nijmegen might be the Netherlands' oldest city, but its sustainable prowess is very much of this century. Explore on two wheels, coasting along the 60km of cycling highways that run through the university town. First stop on a pedal-powered tour? Lange Hezelstraat, a storied shopping district home to numerous independent boutiques, including vintage haven Le Petit Rêve, homeware emporium Dille & Kamille and - where the road merges onto Burchtstraat - sustainable department store Het Duurzame Warenhuis. Stock up on Dutch-made vegan cosmetics, then head across town to the budget-friendly, hostel-style Hotel Nimma. It's not particularly luxurious, but you can save your pennies for a forest-foraged dinner at the three-starred (one of which is green) Restaurant De Nieuwe Winkel, a leader in the city's sustainable dining scene.