Peculiarity always seems impressive and strangely appealing to human nature. While structures with brilliant, almost perfect structural designs are respected, our eyes seem to find it more enjoyable to stare at crooked structures, especially if they’re tilted!
Let’s explore some leaning towers from all around the world.
Tower of Pisa
Architect/Designer: Unknown medieval architects
Construction Year: 1173
Location: Pisa, Italy
Leaning Degree: Approximately 4.0 degrees (reduced from an original lean)
The Leaning Tower of Pisa is probably the world’s most iconic leaning tower. The medieval structure’s construction began in 1173 as part of Pisa’s cathedral complex. It was intended to stand 56 meters (185 feet); however, its foundations began to settle unevenly in the soft ground during its construction. Construction was delayed due to war, but it surprisingly allowed the foundation to settle enough to be stable.
When the construction was resumed, it attempted to balance out the structure, but to no avail. The attempts resulted in the tower’s further sinking. Although its foundations had been strengthened, the Tower of Pisa was at risk of collapse due to its continuous sinking at a yearly rate of 1.2mm (0.05 inch). In 1990, the Leaning Tower of Pisa was closed for a major straightening project, where engineers reduced its lean through soil removal beneath its foundation. The work was completed in 2001; by 2008, the lean had decreased to less than 4.0 degrees. The tower has been reopened since and is likely to remain steady for at least 200 years.
Leaning Tower of Suurhusen
Architect/Designer: Unknown medieval builders
Construction Year: Late Middle Ages
Location: Suurhusen, Germany
Leaning Degree: About 5.19 degrees
The Leaning Tower of Suurhusen is a late medieval steeple that, according to local historian Tjabbo van Lessen, was built during the Middle Ages on marshy ground, with its foundation supported by oak tree trunks preserved by groundwater. However, when the area was drained, the wood rotted, causing the instability of the tower’s foundation and its tilt. In 1975, the church was closed for safety concerns but reopened to the public ten years later.
With an inclination of about 5.19 degrees, the Leaning Tower of Suurhusen surpassed the Tower of Pisa. It held the Guinness World Record for the most leaning tower unintentionally tilted until its German counterpart, the Leaning Tower of Gau-Weinheim, stole the title.
Leaning Tower of Gau-Weinheim
Architect/Designer: Unknown medieval builders
Construction Year: 1749 (converted to a bell tower)
Location: Gau-Weinheim, Germany
Leaning Degree: 5.427 degrees (Guinness World Record)
The Leaning Tower of Gau-Weinheim, located in the small village of Gau-Weinheim, is a medieval fortified tower of the area’s former cemetery fortifications. In 1749, It was converted into a bell tower. While not much information is available about the cause of its tilt, it is likely due to unstable foundations and soft ground.
The Tower holds the Guinness world record as the farthest-leaning church tower, with its lean of 5.427 degrees.
Big Ben
Architect/Designer: Charles Barry and Augustus Pugin (design), Edmund Beckett Denison and George Airy (clock mechanism)
Construction Year: 1859
Location: London, United Kingdom
Leaning Degree: 0.26 degrees
Big Ben is one of the world’s most iconic clock towers. The name refers to the massive bell inside the clock tower at the north end of the Palace of Westminster, although it is often used to describe the entire clock tower.
Standing 96 meters (316 feet) tall, Big Ben is renowned for its accuracy and chimes’ deep, resonant sound. Edmund Beckett Denison and George Airy designed the clock mechanism. The tower is part of the more extensive Gothic Revival architecture of the Palace of Westminster, designed by Charles Barry and Augustus Pugin.
While it is renowned for its uniqueness in London’s skyline, Big Ben has a slight tilt. This lean, caused by changing ground conditions, was discovered during the planning of the Jubilee Line extension. Though the tower leans 0.26 degrees to the northwest, only a fraction of the Leaning Tower of Pisa’s tilt remains structurally sound and is expected to be safe for thousands of years.
Kiipsaare Lighthouse
Architect/Designer: Maximilian Arronet and Otto de Fries
Construction Year: 1933
Location: Kõruse-metsaküla, Saare County, Estonia
Leaning Degree: Not specified; known for its lean due to erosion
The Kiipsaare Lighthouse was built in 1933 by Maximilian Arronet and Otto de Fries to aid navigation. Initially positioned 100 meters from the shore, erosion brought the sea to the tower’s base by the 1990s, causing it to tilt and earn the nickname “Estonia’s Pisa Tower.” However, in 2008, natural forces straightened the lighthouse again.
Despite being decommissioned as a navigational aid in 2009, Kiipsaare remains famous for its unique history, scenic location within Vilsandi National Park, and its appearance in the film Somnambuul.
Menara Condong Teluk Intan
Architect/Designer: Unknown
Construction Year: 1885
Location: Teluk Intan, Perak, Malaysia
Leaning Degree: Not specified; known for its lean due to soft soil foundations
The Teluk Intan Leaning Tower, constructed in 1885, stands 25 meters (82 feet) tall and originally functioned as a water reservoir for the town and provided a vital supply during droughts and emergencies like fires. Additionally, it served as a navigational beacon for ships entering Teluk Anson Port.
The tower, designed in the shape of an 8-storey Chinese pagoda, is actually a 3-storey wood and brick building. Since it began leaning over due to soft soil foundations, it became a clock tower and a prominent tourist attraction in Teluk Intan.
Kilmacduagh Round Tower
Architect/Designer: Unknown
Construction Year: 7th century
Location: Kilmacduagh, Co. Galway, Ireland
Leaning Degree: Not specified; noticeable lean due to foundation issues
Kilmacduagh Monastery, located in County Galway, Ireland, is a historic and picturesque monastic site founded in the 7th century by Saint Colman. The monastery was an important center of learning and religious activity during the early Christian period in Ireland.
Amongst the medieval ruins of the monastery lies the 34-meter (112 feet) tall Kilmacduagh Round Tower. Not only is it Ireland’s tallest round tower, but it is also renowned for its noticeable lean, potentially caused due to the tower’s construction over an existing graveyard with unsolid grounds for the foundation. The lean may have also been caused by the tower’s shallow foundations, an observation revealed by archaeologist Cóilín Ó Drisceoil, who studied other round towers. However, the structure is considered stable and is expected to endure for centuries.
Minaret of the Nouri Mosque
Architect/Designer: Unknown, under Seljuk ruler Nur al-Din
Construction Year: 1172
Location: Mosul, Iraq
Leaning Degree: Not specified; significant lean noted historically
The Great Mosque of al-Nuri and its iconic leaning minaret, which has towered over Iraq’s second-largest city for over eight centuries
The minaret of the Great Mosque of al-Nuri, known locally as al-Hadba’ or “the hunchback” due to its noticeable tilt, was a landmark in the old city of Mosul. Constructed in 1172 under Seljuk ruler Nur al-Din, this 45-meter tall minaret featured decorative brickwork and was part of a larger religious complex, including a mosque and madrassa. By the 14th century, when the Moroccan traveler Ibn Battuta visited, the minaret was already leaning significantly.
Despite renovations in the 1940s that altered the mosque and madrassa, the leaning minaret remained a prominent and iconic feature of Mosul, even appearing on the Iraqi 10,000-dinar banknote since 2003.
The mosque and its unforgettable minaret, along with many other Iraqi monuments, have unfortunately been destroyed during the civil conflicts in Iraq.
Two Towers
Architect/Designer: Unknown
Construction Year: 1109–1119
Location: Bologna, Italy
Leaning Degree: Asinelli Tower (less lean), Garisenda Tower (4 degrees)
The Asinelli (taller one) and the Garisenda are two towers said to have been built by rival families between 1109 and 1119. However, after they were built, the ground shifted, causing both towers to lean. In the 14th century, the Garisenda’s height was shortened from 60 meters (197 feet) to 47 meters (154 feet) to avoid collapse. The Garisenda has a 4 degree lean, while its counterpart, the Asinelli, which is double its height, leans at a smaller angle and is open for visitors.
The towers are under constant surveillance for any alterations. Recent sensor data has indicated signs of increasing degradation in the materials constituting the base of the Garisenda Tower, and measures have been taken to preserve the tower and protect people in case of a collapse.
Leaning Tower of St. Moritz
Architect/Designer: Unknown
Construction Year: 12th century
Location: St. Moritz, Switzerland
Leaning Degree: Expected to reach 5.4 degrees between 2025 and 2030
The Leaning Tower of St. Moritz dates back to the 12th century and was part of the adjacent St. Mauritius church. Landslides caused the church to be demolished; however, the Leaning Tower of St. Moritz stands as a testament to Swiss engineers’ dedication and efforts to preserve and stabilize the structure.
The structure is expected to reach a 5.4-degree lean between 2025 and 2030, and new solutions must be done to avoid this, presenting a new engineering challenge.
