A living landmark
of Copenhagen
since 1642

LIGHT YEAR 2026

From February and all through 2026, you can enjoy special exhibitions, concerts and family-friendly events – all celebrating the 350th anniversary of Ole Rømer’s discovery of the speed of light.

What's on

Ole Rømer and the Great Discovery

Exhibition

The Library Hall

06. Feb - 03. Jan
Light Echoes

Exhibition

The Library Hall

02. Oct - 03. Jan
Look Through the Telescope

Astronomy

The Observatory

05. Oct - 31. Mar
Award Ceremony for the Photo Competition

Special event

05. Oct
Culture Night with stargazing, winning photos and lighttrail

Autumn Break, Culture Night, For children

09. Oct
Workshop: Make your own artwork with light and cyanotype

For children, Workshop

11. Oct
See Saturn during the fall break

Astronomy, Autumn Break, For children, Observatory

12. Oct - 16. Oct
ROUND TOWER CLASSICS: NOVO Quartet

Concert

The Library Hall

29. Oct

Listen to the Tower

Did a car really drive up the Round Tower’s Spiral Ramp? How often did famous fairy tale writer Hans Christian Andersen visit the tower? Immerse yourself in our audio stories, and find out.

Photography Competition: “Capture the Light in the Round Tower”

On the occasion of Year of Light 2026, marking the 350th anniversary of Ole Rømer’s discovery of the speed of light, Rundetaarn invites photographers — whether professional, amateur, or hobbyists — to take part in a competition focusing on light and architecture in Rundetaarn and the Trinitatis Complex.

A Virtual Tour of the Tower

Visit the tower from home with our virtual tour. Here, you can move up the Spiral Ramp, visit Trinitatis Church, scope out the current exhibition in the Library Hall and marvel at the 360 degree view of Copenhagen’s rooftops.

Guided Tours for Groups

A guided tour offers an extra dimension to a visit by telling the stories of the tower and the people who have come here since 1642.

Good to Know

Prams, guide dogs, wheelchairs and luggage. Read more about the practicalities before your visit to the Round Tower.

Plan your visit

Practical information

Find out prices, means of payment and more info profitable to a visit in the Round Tower.

THE TOWER

Measure and Weight

How long is the Spiral Ramp? How much does the Round Tower weigh? How large is the Library Hall?

ASTRONOMY

The Observatory

King Christian IV erected the tower to enable astronomers from the University of Copenhagen to gaze at the stars above the lights and smoke of the city.