On the northern edge of the city is Frilandsmuseet, the largest open-air museum in the world. A proper trip here would take all day, though there are museum guides designed to help you get in and out more quickly if you're short on time. The buildings here date from the 17th to the 19th century, and have been maintained with period-appropriate decor relating to Danish rural life. They include peasants' cottages, farmhouses, windmills, fishermen shacks, firehouses, and factories, all presented without signage as if you had just wandered into the past. Admission is free, but you will need to take two trains to get here.