Conservation ratings have fallen sharply since 2020, with 53 properties now on the official danger list — yet the World Heritage register continues to grow
The condition of the world’s most celebrated cultural and natural landmarks is deteriorating faster than the body charged with protecting them can respond, according to a growing body of assessment work led by the International Union for Conservation of Nature. Its most recent World Heritage Outlook, presented in October 2025, found that the share of natural sites with a positive conservation outlook has dropped to 57 per cent. Fifty-three properties now sit on UNESCO’s List of World Heritage in Danger. The findings come as bombardment in Iran, mass tourism in Asia and accelerating climate stress converge on sites spanning more than 160 countries.
A measurable slide in condition
The IUCN’s figure of 57 per cent marks a clear break from the recent past. The proportion had held firm at 63 per cent across three previous assessments in 2014, 2017 and 2020. Over the same five-year window, the share of properties judged to be of “significant concern” or “critical” rose from 37 per cent to 43 per cent.
The danger list itself was designed as a warning mechanism rather than a sanction, intended to marshal international attention and resources. In practice, its reputation has drifted. Christina Cameron, Professor at the School of Architecture and Canada Research Chair on Built Heritage at the University of Montreal, has observed that some governments regard inclusion as a “black list”, and that the mechanism has at times been used to apply political pressure rather than to advance conservation.
Removal from the register altogether remains exceptionally rare. Only three properties have ever been struck off: Oman’s Arabian Oryx Sanctuary in 2007, after its protected area was reduced by 90 per cent; the Dresden Elbe Valley in 2009, following construction of a road bridge across the city’s baroque riverscape; and Liverpool’s Maritime Mercantile City in 2021, after the World Heritage Committee found that waterfront redevelopment, including a proposed Everton stadium, had irreversibly eroded the qualities that gave the site its outstanding universal value.
When recognition becomes a magnet
Designation carries commercial weight, and that weight has consequences. Angkor Wat in Cambodia now draws more than two million visitors annually, supporting a resort town on its doorstep. Niagara Falls sits ringed by casinos and hotels. In each case the heritage listing helped generate the very tourist traffic that reshaped the surroundings.
Beijing offers the starkest example. Following the Forbidden City’s inscription in 1987, wide areas of the surrounding old quarter were cleared. Courtyard homes and hutong alleys were pulled down and replaced with enlarged replicas and purpose-built heritage streets serving visitors, displacing long-established residents. Zhang Jie, a professor of architecture at Tsinghua University who spent 20 years working on the preservation of the capital’s historic fabric, has warned that whole historic cities risk being levelled or made uniform in pursuit of a look that bears little relation to their actual past.
By the 1990s almost 40 per cent of Beijing’s hutongs had already gone, cleared for roads and towers. Research examining the city’s Master Plan attributed much of the loss to vague drafting — the absence of workable definitions for “style” and “harmony” in new building work — with 77 per cent of traditional siheyuan courtyard housing destroyed, some 9.7 million square metres, together with around 7,000 lanes. The city designated 25 historical protection zones by 2005 and gave special status to certain threatened alleys. Even so, academic studies have documented how officials working to fixed deadlines, particularly before the 2008 Olympics, prioritised urban beautification over conservation and stepped up demolition of buildings classed as run-down.
A wall disappearing by degrees
The Great Wall of China, listed in 1987, shows how little a designation counts for against sustained local pressure. Analysis by the Chinese Association of Cultural Relics estimated that roughly a third of the structure had already vanished. A 2018 survey of Great Wall resources found just 12.3 per cent of preserved sections in good condition, with 51.2 per cent surviving only as traces or gone entirely.
In September 2023 two construction workers in Shanxi province were arrested after driving an excavator through a Ming Dynasty section to create a shortcut to a nearby building site. Police said the damage could not be undone. Elsewhere, bricks and stone continue to be removed illegally for private building, while mining, road schemes and industrial activity destabilise the ground around it. Hundreds of thousands of visitors a year wear down its steps and paths.
Climate is now compounding all of it. A global study published in 2025 found that 80 per cent of World Heritage properties are already under climate stress, with almost one in five built from stone or timber, materials especially exposed to changing conditions. The rammed-earth stretches in Gansu province are particularly vulnerable to salt erosion, temperature swings and desertification.
Chinese authorities have invested heavily in response. Repairs are carried out by hand rather than machine, using local clay bricks, traditional lime mortar and stone quarried nearby. Since 2021 a joint team from the Beijing University of Civil Engineering and Architecture and the Beijing Great Wall Cultural Research Institute has tracked environmental vibration using the BeiDou satellite system, radar and weather monitoring — a shift towards preventing damage rather than repairing it. The wall’s sheer length, however, places most of it beyond the reach of such monitoring.
Documented, not defended
Conflict destroys in weeks what development erodes over decades. The demolition of ancient sites across Syria and Iraq by Islamic State demonstrated the limits of UNESCO’s reach: the organisation could record the losses but could not stop them.
That pattern has returned. US and Israeli strikes on Iran have damaged at least four cultural and historical sites, among them palaces and an ancient mosque. UNESCO confirmed verified damage to the Qajar-era Golestan Palace in Tehran, the 17th-century Chehel Sotoun Palace in Isfahan, the Masjed-e Jame — Iran’s oldest Friday mosque — and buildings close to the prehistoric sites of the Khorramabad Valley. Iranian officials estimate that restoring the Golestan Palace’s mirror hall alone could take 15 years.
Ahmad Alavi, who heads the heritage committee of Tehran city council, said airstrikes had damaged at least 120 culturally or historically significant sites nationwide since the war began. Iran’s Ministry of Cultural Heritage, Tourism and Handicrafts put the number of damaged museums, monuments and cultural sites at 56 or more. Israel’s White City of Tel Aviv and the ancient site of Tyre in southern Lebanon have also been affected.
UNESCO said it had passed the coordinates of every World Heritage site to all parties before fighting started, so that precautions could be taken. Its remaining instruments are documentation, coordination and persuasion. Iran and Lebanon have jointly asked for further sites to be added to the enhanced protection list.
Authority without enforcement
The underlying constraint is structural. UNESCO depends on the voluntary cooperation of sovereign states; it can list, monitor, caution and, in the last resort, delist, but it cannot halt a building project, stop a military operation or curb commercial demand.
The Palace of Westminster demonstrates the point on a smaller scale. Successive tower schemes along the South Bank prompted UNESCO to warn that the site’s setting was being permanently harmed, and it raised the prospect of adding Westminster to the danger list. The threat was later withdrawn after lobbying by Britain’s ambassador to the organisation, prompting campaigners to ask what the status secures in practice. Comparable questions have since been raised over the Tower of London and nearby development.
The IUCN has noted that UNESCO has invoked the danger list without applying it in numerous cases where a state could readily have addressed the problem, and has argued that leaving properties on the register for extended periods is itself open to challenge, with other conservation routes worth pursuing.
Some progress has come from industry. As of February 2026, more than 50 companies and trade associations have made formal “no-go” commitments, undertaking not to carry out or finance damaging activity inside World Heritage sites, their buffer zones or wider settings. Those pledges carry no legal force.
The register now exceeds 1,000 properties and continues to grow each year, more than four decades after the programme began.
