By Marc Pulisci
The Leaning Tower of Pisa, a UNESCO World Heritage site, has been tilting since its construction began in 1173 due to an unstable foundation. In recent years, attempts have been made to secure and partially straighten the structure using large pylons and steel cables.
Engineering techniques that were previously used to stabilize the Leaning Tower of Pisa are now being employed to safeguard the Torre Garisenda in Bologna, another inclined landmark in Italy. This initiative, which aims to prevent further tilting, is focused on a 157-foot-tall tower.
The Garisenda Tower, towering over Bologna's Old Town alongside another 12th-century structure, was initially built with a tilt, as explained by Tomaso Trombetti, a structural engineering professor at the University of Bologna. This imbalance occurred because one side of the tower's foundation settled faster than the other during construction, leading to a dangerous four-degree lean over time. In contrast, Bologna's taller Asinelli Tower, standing at 319 feet, does not exhibit a significant lean.
Guido Gottardi, a geotechnical engineering professor at the University of Bologna, mentions that the same pylons used in the 1993-2001 Pisa restoration will support Torre Garisenda. These pylons, anchored into the subsoil, serve as a stabilizing force during the tower's structural reinforcement. Additionally, fundraising efforts are in progress to support the restoration of these historically significant towers.
This tower stands among numerous historic sites requiring preservation efforts to prevent deterioration. Factors contributing to their decline include not only natural wear but also issues like theft, excessive tourism, industrial impacts, and climate change. Conservationists are actively working to protect five other similarly at-risk architectural wonders.
Hurst Castle, Hampshire, England
Constructed by King Henry VIII in 1544, Hurst Castle in Hampshire, England, was established for defense against European invaders. Despite its historical resilience, the relentless forces of nature, including fierce storms, rising sea levels, and the continuous assault of waves, have eroded its foundation. This natural battering led to the partial collapse of the castle's eastern battery in 2021, highlighting the ongoing battle between human heritage and the power of nature.
Following the collapse, approximately 22,000 tons of rock and shingle have strengthened Hurst Castle. English Heritage, which oversees the site, utilized terrestrial laser scanning to generate 3D models, aiding in the evaluation of optimal restoration techniques, according to Ron Blakeley, the national project manager. Visitors can access the castle from April to early November via a brief boat trip, allowing exploration of its weaponry and gun tower.
Located 260 miles south of Cairo in a dry valley, Abydos hosts an extensive temple complex and burial ground for early Egyptian pharaohs, with constructions dating back approximately 5,900 years. Present-day visitors have the opportunity to navigate the ancient stone-columned corridors, admire detailed carvings dedicated to Pharaoh Seti I, and explore the Osireion, an underground structure possibly built in tribute to Osiris, the deity of the afterlife in Egyptian mythology.
Looting has significantly impacted Abydos, with artifacts being removed since ancient times and illicit excavations occurring recently. This has made Abydos one of Egypt's most secure yet less visited archaeological sites. According to Johnathan S. Bell from the World Monument Fund, the strict security measures and lack of facilities for tourists have led to fewer people visiting the site.
To address the deterioration of the complex, the Egyptian government, along with the World Monument Fund and other organizations, have initiated numerous restoration efforts. These efforts include the meticulous restoration of vivid wall friezes and the addition of steel supports to stabilize the Osireion's vulnerable areas.
Murujuga, Western Australia
Murujuga in Western Australia, an open-air gallery with over a million Aboriginal petroglyphs, spans thousands of years. Situated 780 miles north of Perth, it showcases unique carvings like wallabies and kangaroos. However, the site faces threats from industrialization and pollution on the Burrup Peninsula, putting its future at risk.
In February 2024, Indigenous traditional owners of Murujuga celebrated significant achievements in their conservation efforts. The Western Australian government designated approximately 627 acres previously slated for development to the already protected Murujuga National Park. Additionally, a groundbreaking policy was introduced, granting Indigenous communities more control over the site's management, a move praised as a milestone. These efforts are part of a larger initiative to have Murujuga recognized as a UNESCO World Heritage site.
Teotihuacan, Mexico
Thirty miles north of Mexico City, Teotihuacan, a 9,000-acre city built between the 1st and 7th centuries A.D. by an unknown civilization, was once the largest city in the Western Hemisphere. Despite attracting over a million visitors annually and being famous for structures like the Pyramid of the Sun, the site faces challenges from overtourism, weather damage, and past restoration efforts. The World Monument Fund has raised concerns about the unregulated development around the site, threatening potential archaeological discoveries.
Conservation measures for the Temple of Quetzalcoatl have been implemented, such as enhancing drainage, repairing structural cracks, and removing harmful salts from its surface. The World Monument Fund, alongside other organizations, is now advocating for increased local community engagement to develop a plan for sustainable tourism at the site.
Osterman Gas Station, Arizona
The Osterman Gas Station, a 1920s building in Peach Springs, Arizona, holds a special place in the hearts of the local Hualapai people and Route 66 travelers. Constructed from a Sears kit, it served as a social hub for the Hualapai, who later purchased it in 2005 after its closure. Currently, the Hualapai, in collaboration with the National Trust for Historic Preservation, are working on restoring this cherished site, located near the Grand Canyon Skywalk.