Qasr Al Hosn Palace and Fortress is located in the United Arab Emirates, in the center of Abu Dhabi. Qasr Al Hosn is the oldest building in the capital, for a long time the palace was the official residence of the ruling dynasty of Al Nahyan. In 1760-1761, a watchtower was erected at the site of the future fortress by Sheikh Diyyab bin Isoi. It was intended to protect the settlement, which was built at a discovered source of freshwater, and controlled access to the island. Subsequently, the tower was rebuilt into an impregnable fort. For construction, corals and sea stones were used; for the walls, a mixture of lime, sand and crushed sea shells was used. Thanks to the reflective effect of the exterior, the walls of the fort shone in the sun, serving as a guide for merchant ships. For the construction of ceilings, a mangrove tree was used, characterized by strength and durability. In the years 1845-1855, Sheikh Saeed bin Tahnun significantly expanded the fortress, and a small village of palm huts, located next to the fort, in the XIX century turned into a city with a population of more than five thousand. During the exploration and discovery of oil fields, in 1939-1950, the area of Qasr Al Hosn was expanded, a palace was built on the territory of the fortress. In 1966, under Sheikh Zayed bin Sultan Al Nahyan, a large-scale reconstruction of Qasr Al Hosn was carried out, after which the palace turned from the residence of the ruler into a museum and a repository of collections of artifacts, photographs and weapons that tell the story of Abu Dhabi and the Persian Gulf region. In 2008, the fort was closed for a new reconstruction. As it turned out, a white layer of plaster on the walls of the fort accumulates moisture on the coral stones of the building. Currently, work is underway to free the original masonry. Visitors can explore the fortress and palace during the annual Qasr Al Hosn festival. The festival program is full of various theatrical performances and expositions, telling about the birth of the city, the history of the fort, about the life and activities of local residents - Bedouins, sailors, residents of oases and islands. Spectators will be able to watch the construction of national wooden dow boats, pearl mining, and attend craft trade fairs. Within the framework of the festival, concerts of folk songs and poetry, spectacular shows, performances by "horse spellcasters" and exhibitions are held.