linguistic:paraphrasing, quality:corruption, structural:reformatting, structural:summarization
Restoration and challenges

In the 20th century, a considerable effort was launched to clear the plant overgrowth and restore the temple complex. Conservation d'Angkor (Angkor Conservancy) was established by the École française d'Extrême-Orient (EFEO) in 1908. The Conservation d'Angkor was responsible for the research, conservation, and restoration activities carried out at Angkor until the early 1970s with major restoration works undertaken in the 1960s. Cambodia gained independence from France on 9 November 1953 and has controlled Angkor Wat since then.

Restoration work was interrupted by the Cambodian Civil War when the Khmer Rouge took control of the country during the 1970s and 1980s. Work on Angkor was abandoned during the Khmer Rouge era and the Conservation d'Angkor was disbanded in 1975. Camping Khmer Rouge forces used whatever wood remained in the building structures for firewood, and a shoot-out between Khmer Rouge and Vietnamese forces caused a few bullet holes in bas reliefs. In the late 1980s and early 1990s, far more damage was done to the reliefs by art thieves working out of Thailand who lopped off many sculptures and other structures, including earlier reconstructions. As with most other ancient temples in Cambodia, Angkor Wat also faced extensive damage and deterioration by a combination of plant overgrowth, fungi, ground movements, war damage, and theft, though the war damage to Angkor Wat's temples was limited compared to the rest of Cambodia's temple ruins.

Between 1986 and 1992, the Archaeological Survey of India carried out restoration work on the temple as France did not recognise the Cambodian government at the time. Criticisms have been raised about both the early French restoration attempts and the later Indian work, with concerns over the damage done to the stone surface by the use of various chemicals and cement.

In 1992, the site was declared as a UNESCO World Heritage Site. Simultaneously, Angkor Wat was listed in UNESCO's World Heritage in Danger (later removed in 2004) following an appeal for help by Norodom Sihanouk together with an appeal by UNESCO to the international community to save Angkor. Zoning of the area was designated to protect the Angkor site in 1994, Authority for the Protection and Management of Angkor and the Region of Siem Reap (APSARA) was established in 1995 to protect and manage the area, and a law to protect Cambodian heritage was passed in 1996.

In the 21st century, teams from several countries including France, India, Japan and China are involved in Angkor Wat conservation projects. The German Apsara Conservation Project (GACP) was launched to protect the devatas, and other bas-reliefs that decorate the temple from further damage when the organization's survey found that around 20% of the reliefs were in very poor condition mainly because of natural erosion and deterioration of the stone, but also in part also due to earlier restoration efforts. Microbial biofilms degraded sandstone at Angkor Wat. Other work involved the repair of collapsed sections of the structure and prevention of further collapse. For example, the west facade of the upper level was buttressed by scaffolding in 2002. A Japanese team completed the restoration of the north library of the outer enclosure in 2005. Replicas have been made to replace some of the lost or damaged sculptures.

In December 2015, it was announced that a research team from the University of Sydney found a previously unseen ensemble of buried towers that were built and demolished during the construction of Angkor Wat, as well as a massive structure, with wooden fortifications, of unknown purpose on its south side. The findings included evidence of low-density residential occupation, a road grid, ponds and mounds in the region. These discoveries indicated that the temple precinct, bounded by a moat and wall, may not have been used exclusively by the priestly elite, as was previously thought.