The Rundetaarn, or Rundetårn (Round
Tower in English), is a
17th-century tower located in central Copenhagen, Denmark. One of the
many architectural projects of Christian IV, it was built as an
astronomical observatory. It is most noted for its equestrian
staircase, a 7.5-turn helical corridor leading to the top, and for the
expansive views it affords over Copenhagen.
The tower is part of the Trinitatis Complex which also provided the
scholars of the time with a university chapel, the Trinitatis Church,
and an academic library which was the first purpose-built facilities
Copenhagen University Library which had been founded in 1482.
Today the Round
Tower serves as an observation tower for expansive
views of Copenhagen, a public astronomical observatory and a
historical monument. At the same time the Library Hall, located above
the church and only accessible along the tower's ramp, is an active
cultural venue with both exhibitions and a busy concert schedule.
1.2 Planning and preparations
1.3 Construction phase
1.4 Time as an observatory
1.5 Demise and later years
1.6 Notable ascents
2.1 Spiral ramp
2.2 Observation deck
4 The Round
4.1 Public observatory
4.2 Exhibitions and concerts
5 Cultural references
6 See also
8 External links
Rundetaarn. Illustration from the architect Laurids de Thurah's Hafnia
hodierna of 1748.
Astronomy had grown in importance in
17th-century Europe. Countries
had begun competing with each other in establishing colonies, creating
a need for accurate navigation across the oceans. Many national
observatories were therefore established, the first in 1632 at Leiden
in the Dutch Republic. Only five years later the Round Tower
Observatory, first referred to as STELLÆBURGI REGII HAUNIENSIS, would
Planning and preparations
Rundetaarn Observatory, as depicted Johann Doppelmayr's
map of the southern celestial hemisphere, ca. 1742.
Tycho Brahe had fallen out of favour and left Denmark, Christian
Longomontanus had become Christian IV's new astronomer and the first
professor of astronomy at the University of Copenhagen. In 1625 he
suggested the king build an astronomical tower as a replacement for
Stjerneborg which had been demolished after his death in
Longomontanus' initial proposal was to erect the new observatory on
the top of the hill Solbjerget, now known as Valby Bakke. But since
there were also plans for the construction of a new students' church
and a library for the university, the idea of merging the three
buildings into one grand complex emerged.
Already in 1622, Christian IV had bought the land where it was
ultimately decided to build the Trinitatis Complex. His original plans
for the site are not known but as it was conveniently located next to
Regensen dormitories and the university, it was chosen for his new
Although there is no clear proof, it is generally accepted that Hans
van Steenwinckel the Younger was charged with the commission to design
the new edifice though he did not live to see the tower completed.
Cross section of the tower and the church from Thurah's Hafnia
From 24 November 1636, stones were brought to the site for the
foundation, first from the city's ramparts and later from the area
around Roskilde. Bricks were ordered from the Netherlands since local
manufacturers could not meet the high quality standards requested. In
February 1637, a contract was signed with a Henrik van Dingklage in
Emden for the supply of bricks for the construction. The first three
ship loads were to be delivered in May, the next three loads the
following month and the remainder on demand.
The Trinitatis Complex was set for construction in a crowded
neighbourhood of narrow streets and alleyways. The area first had to
be cleared. On 18 April 1637, 200 men, soldiers and personnel from
Bremerholm began to demolish the half-timbered houses occupying the
The foundation stone was laid on 7 July 1637. When Hans van
Steenwinckel died on 6 August 1639,
Leonhard Blasius was brought to
Denmark from the Netherlands as new Royal Building Master. Unlike his
predecessor, he would become a mere transitional figure in Danish
architecture, dying just four years after his arrival in the country
without leaving any notable buildings of his own design. On several
occasions construction work came to a standstill due to shortage of
funds. Churches in
Denmark and Norway were therefore ordered to
contribute a share of their earnings during the construction years.
In 1642, the tower was finally completed, though the church was
completed only in 1657 and the library in 1657.
Time as an observatory
Christian Longomontanus became the first director of the observatory.
In the Great Fire of 1728 the Trinitatis Complex was severely damaged
but was rebuilt.
Demise and later years
Rendering made by
Anton Rosen in connection with his proposal to move
the towerto a position next to the church
During the early 19th century, the Round
Tower became outdated as an
astronomical observatory. Instruments were growing still larger while
the tower could not be expanded and, at the same time, light pollution
from the surrounding city and vibrations caused by the ever increasing
traffic in the streets below had made the observations inaccurate.
The University therefore decided to build
Østervold Observatory on
the old bastioned fortifications of the city, which had become
outdated and were being decommissioned. The new observatory was
inaugurated in 1861 to the design of Christian Hansen.
In 1716, The Czar
Peter the Great
Peter the Great ascended the staircase on horseback
while visiting Copenhagen. His wife, Catherine I, reportedly ascended
behind him in a carriage.
In 1902, a Beaufort car was the first motorised vehicle to ascend this
A medal in the Round Tower's collection of medals indicates that the
first bicycle race held in the tower took place as early as 1888,
possibly in connection with The Nordic exhibition of Industry,
Agriculture, and Art.
In 1911, the newspaper Socialdemokraten arranged a bicycle race down
the Round Tower.
Ole Ritter won a bicycle race against
Leif Mortensen up the
Tower in a time of 55.3 seconds.
Henrik Djernis won a bicycle race against
Jens Veggerby in a
time of 50.05 seconds.
In 1989, Thomas Olsen went up and down the Round
Tower on a unicycle
in 1 minute and 48.7 seconds, which is a world record.
Rundetaarn seen from Krystalgade
Tower is a cylindrical tower built in masonry of alternating
yellow and red bricks, the colours of the Oldenburgs. The bricks used
were manufactured in the Netherlands and are of a hard-burned, slender
type known as muffer or mopper. On the rear side, it is attached to
the Trinitatis Church, but it has never served as a church tower.
Steenwinckel — whose name is otherwise synonymous with Dutch
Renaissance architecture in
Denmark — with the Trinitatis Complex
has left his signature style. Unlike his other buildings with their
lavish ornamentations and extravagant spires, the complex is built to
a focused and restrained design. Hans van Steenwinckel must have been
up on the situation in Holland, cogniziant that the style which he had
once learned from
Hendrick de Keyser had been altogether abandoned.
The architects now setting the agenda in the Netherlands, masters such
Jacob van Kampen
Jacob van Kampen (Amsterdam City Hall),
Pieter Post (
the Hague) and Philip Vingboons, now favoured a style characterized by
sobriety and restraint. It is now known as Dutch Baroque or sometimes
Dutch Classicism. Its proponents often relied on the theoretical works
such as those of
Palladio and of Jacopo Barozzi da Vignola.
Steenwinckel may have paid a visit to his native Netherlands prior to
his change in style but it will have been too early for him to have
seen any of the period's buildings realized.
Inside view of the spiral ramp
Instead of stairs, a 7.5-turn spiral ramp forms the only access way to
the towertop observatory as well as the Library Hall and the
Bell-Ringer's Loft, both located above the church. The ramp turns 7.5
times around the hollow masonry core of the tower before reaching the
observation deck and observatory at the top, on the way also affording
access to the Library Hall as well as the Ringer's Loft. This design
was chosen to allow a horse and carriage to reach the library, moving
books in and out of the library as well as transporting heavy and
sensitive instruments to the observatory.
The winding corridor has a length of 210 m, climbing 3.74 m
per turn. Along the outer wall the corridor has a length of
257.5 m and a grade of 10%, while along the wall of the inner
core the corridor is only 85.5 m long but has a grade of 33%.
The observation deck is located 34.8 m above street level. Along
the edge of the platform runs a wrought-iron lattice made in 1643 by
Kaspar Fincke, Court Artist in metalwork. In the latticework,
Christian IV's monogram and the letters RFP are seen, the letters
representing the King's motto: Regna Firmat Pietas – Piety
strengthens the Realms.
Inside view of the rebus inscription on the façade
The observatory is a small domed building, built on the roof of the
tower. Built in 1929, the current observatory is 7 m high and has
a diameter of 6 m. Access is by a narrow winding stone staircase
from the observation deck.
On the upper part of the façade of the tower, there is a gilded rebus
inscription. Christian IV's draft of it, written in his own hand
writing, is kept at the Danish National Archives. The rebus includes
the four Hebrew consonants of the Tetragrammaton. The rebus can be
interpreted in the following way: Lead God, the right teaching and
justice into the heart of the crowned King Christian IV, 1642.
The tower contains a toilet used by the researchers and astronomers
working in the tower and consisting of a seat almost at the top and a
shaft leading down to the bottom floor built into the hollow core.
This shaft has no way of emptying it nor any ventilation to the
outside, making it arguably one of the world's largest and earliest
Today the Round
Tower serves as an observation tower, a public
astronomical observatory, an exhibition and concert venue and a
In 1860 the University of
Copenhagen decommissioned the Round
a university observatory but in 1928 it was reconstructed as an
observatory with access for amateur astronomers and the general
public. It is open from mid-October to mid-March.
The Library Hall
Exhibitions and concerts
Since 1987, the Library Hall which lies above The Trinitatis Church,
has served as an exhibition space, featuring various exhibitions of
art, culture, history and science. At the same time, it is used as a
concert venue, every year hosting around a hundred concerts.
The observation deck affords extensive views over the rooftops of the
old part of
Copenhagen with its many spires, including the Marble
Church, the Nikolaj contemporary art center, Christiansborg Palace,
Christiansborg Slotskirke (da), the Church of the Holy Ghost,
Copenhagen City Hall, Palace Hotel, the Church of Our Lady, St.
Peter's Church, the Great Synagogue, St. Andrew's Church, Rosenborg
Castle, the Church of Our Saviour and the pipes of
Amagerværket (da). On clear days, both the Øresund Bridge
and Sweden can be seen in the distance.
Every year in spring, a unicycle race is held in the Round Tower. The
contestants have to go up and down the tower. The world record, set in
1988, is 1 minute and 48.7 seconds.
In Hans Christian Andersen's fairy tale The Tinder Box, the largest of
the three dogs is said to have eyes as large as the Round
Hans Christian Andersen
Hans Christian Andersen fairy tale, The Elder-Tree Mother,
an old married couple remembers how they used to go "up the Round
Tower, and looked down on Copenhagen, and far, far away over the
water; then we went to Friedericksberg, where the King and the Queen
were sailing about in their splendid barges!".
In Hans-Christian Andersen's novel, To Be, or Not To Be, the main
character, Niels Bryde, is born and grows up in the Round Tower, where
his father is a gatekeeper.
A 1:3 scale replica of the tower has been built in the
originally-Danish-settled city of Solvang, California.
5505 Rundetårn commemorates the tower.
In Denmark, heights of buildings are often compared to the height of
A phrase in Danish is "Which is highest, the
Rundetaarn or a crash of
thunder?" (loud and high are the same word in Danish). It is often
used in a discussion when the opponent tries to compare incomparable
quantities - see also Apples and oranges.
Featured in "SimCity (2013 video game)".
Architecture of Denmark
^ "Centuries of Astronomy Astronomy in Denmark". Rundetaarn. Archived
from the original on 2009-02-02. Retrieved 2009-12-01.
^ "Hans van Steenwinckel". answers.com. Retrieved 2009-11-26.
^ a b "Bygningen af Rundetaarn". Rundetaarn. Retrieved
^ a b c d "Trinitatis Kirke og Rundetaarn". kloakviden.dk. Archived
from the original on 2011-01-09. Retrieved 2009-12-02.
^ "Østervold". Danmarks Natur- og Lægevidenskabelige Bibliotek.
^ a b "Sære måder at bestige tårnet på". Rundetaarn. Archived from
the original on 2009-05-23. Retrieved 2009-08-18.
^ "Mål og vægt". Rundetaarn. Retrieved 2009-08-02.
^ a b "The Tower". Rundetaarn. Retrieved 2009-08-02.
^ "Views from the Round Tower, November 2016". Independent Travellers.
independent-travellers.com. Retrieved September 5, 2017.
^ "The elderbush". andersenstories.com. Retrieved 2009-06-23.
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