West of Kongens Nytorv, the city’s largest square and home to some of the best hotdog stalls in town, pedestrianized Strøget leads into the heart of Indre By. This is Denmark’s premier shopping area. The quirky 35m-high Rundetaarn (Round Tower; mid-March to mid-May daily 10am–6pm; mid-May to mid-Sept daily 10am–8pm; mid-Sept to mid-Oct daily 10am–6pm; mid-Oct to mid-March Thurs–Mon 10am–6pm, Tues & Wed 10am–9pm; 25kr) dominates the skyline north of Strøget. Built as an observatory and finished in 1642, the main attraction is the view from the top, reached via a spiral walkway. A glass floor 25m up allows you to look down into the core of the tower. It’s a still-functioning observatory, and you can view the night sky through its astronomical telescope (May–Sept 10am–8pm; Sept–May 10am–6pm).