The Round Tower

A Monument to Royal Vision and Scientific Curiosity

The Round Tower stands as one of Copenhagen's most distinctive landmarks, erected in 1642 by King Christian IV as part of the Trinitatis Complex. This architectural marvel was conceived as a triple-purpose structure: an astronomical observatory at its summit, a university library on the floor above Trinity Church, and the church itself at its base. The tower's construction began with the laying of the cornerstone on July 7, 1637, and was completed five years later, representing a significant investment in both scientific advancement and royal prestige during Denmark's Golden Age.

The Iconic Spiral Ramp and Ascent Experience

The tower's most distinctive feature is its famous spiral ramp—the only one of its kind in Denmark—which winds 7½ times around the tower's hollow core. This 200-meter continuous ramp eliminates the need for stairs during most of the ascent, making the climb accessible to visitors of varying fitness levels. The ramp features small niches that serve as pleasant resting spots for adults and popular hiding places for children. Approximately two-thirds of the way up, visitors encounter a glass-bottomed viewing platform suspended above the hollow core—a striking and slightly nerve-racking photo opportunity. The final ascent involves two sets of stairs: a wide wooden staircase and a smaller winding stone staircase leading to the open-air viewing deck at the summit.

Panoramic Views and the Observatory

From the top of the tower, visitors enjoy one of Copenhagen's finest panoramic vistas, stretching from the spires of the old town to the Øresund coast. On clear days, the view extends across the water to Sweden. The open-air platform offers sightlines to Copenhagen Cathedral, St. Nicolas Church, Rosenborg Palace, and the Marble Church. The Observatory at the summit remains an active astronomical facility. During the winter season from October to March, astronomers staff the observatory on Tuesday and Wednesday evenings from 6 to 9 PM, allowing visitors to observe planets and celestial objects through the tower's large telescope. During select summer Sundays, the sun and sunspots can be observed through a protective filter.

The Library Hall: From Scholarship to Contemporary Culture

Halfway up the spiral ramp lies the Library Hall, a bright and beautiful space that once housed the entire University of Copenhagen book collection—over 10,000 volumes. The hall served as the university library until 1861 and was restored in 1987 as a contemporary exhibition and event space. Today, it hosts rotating exhibitions spanning art, science, and history, alongside concerts, lectures, talks, and cultural events. The Library Hall also contains the Round Tower's shop and café, where visitors can purchase books, posters, and souvenirs while enjoying refreshments. The hall's transformation from a scholarly repository to a vibrant cultural venue reflects the tower's evolution as a living landmark.

Modern Role and Visitor Experience

The Round Tower attracts over 650,000 visitors annually, making it one of Copenhagen's most popular attractions. The tower operates 362 days a year, with extended hours during summer months. Admission is straightforward: adults pay 60 DKK, students 40 DKK, and children under 17 enter free (children under 11 must be accompanied by an adult). Tickets are purchased directly at the tower's ticket office with no advance booking available. The tower has a maximum capacity managed by staff, and during peak hours, queuing may occur, though waits typically do not exceed 20 minutes. Traffic to and from the viewing platform is regulated by a traffic light to manage flow safely.

Restoration and Future Vision

In 2026, the nearly 100-year-old copper dome of the observatory undergoes restoration to preserve this cultural heritage for future generations. The dome, which has developed leaks, receives new copper cladding, and the observatory interior is refurbished, including renewal of the floor and restoration of the historic refractor telescope by specialist craftspeople. Throughout 2026, the Round Tower hosts four special exhibitions and a rich program of music and events exploring the theme of light, demonstrating the tower's continued vitality as a cultural institution.