The Round Tower (Rundetaarn)

Rundetaarn (Købmagergade)

A 400-year-old observatory you climb by a spiral ramp, no stairs

Hours

Oct–Mar: Mon–Tue 10am–9pm, Wed–Sun 10am–6pm; observatory Mon–Tue 6–9pm, weather permitting

Tickets

Adults DKK 60, students DKK 40, under-18s free (official site); buy at the door

Address

Købmagergade 52A, 5 minutes' walk north of Strøget

Christian IV built this as an observatory in the 1640s. Instead of stairs, a brick-paved spiral ramp winds up inside, wide enough that Peter the Great is said to have ridden a horse up it. Halfway up, the old university library hall is now an exhibition space, and the platform at the top looks over the old town's roofs and spires at close range. It's lower than Christiansborg's tower, which is exactly why the streets feel so close.