Children play in an outdoor shower as a soldier takes part in a surprise operation in the Manguinhos slum in Rio de Janeiro, Brazil, Thursday, January 18, 2018. Troops have been sent to Rio due to the increase of the violence, and in an attempt to help restore order, but so far have had little impact. The operation on Thursday took place three weeks ahead of Carnival, when thousands of tourists are expected to arrive in the city. (Photo by Leo Correa/AP Photo)

A mahout watches the Thai animation movie Kan Kluay with his elephant in Ayuthaya province, about 80km (49 miles) north of Bangkok June 5, 2006. The movie tells the story of a young Thai wild elephant who, while looking for his father, becomes the war elephant of the Thai King fighting against Burma and restored Thailand's ancient Ayuthaya empire that existed about 400 years ago. (Photo by Sukree Sukplang/Reuters)

The Rakotzbrücke bridge in the autumnal azalea and rhododendron park in Kromlau in the district of Görlitz, Saxony near the state border with Brandenburg on November 7, 2023. More than four million euros have been invested in the restoration and reconstruction of this Lusatian landmark in recent years. The complex includes the listed group of Rakotzbrücke bridges and the so-called organ made of basalt. Friedrich Hermann Rötschke had these built between 1842 and 1875. (Photo by Patrick Pleul/dpa)

Russian participants adjust their hair, preparing for the Kremlin Cadet Ball in Moscow, Russia, 08 December 2016. Pupils of cadet schools from different parts in Russia gathered for the first Kremlin Ball, restoring an old tradition of Russian officers and noble girls. (Photo by Sergei Chirikov/EPA)

(L-R) American actor Chase Stokes, American singer-songwriter Kelsea Ballerini and American comedian Tiffany Haddish seen backstage during the 2023 Video Music Awards at Prudential Center on September 12, 2023 in Newark, New Jersey. (Photo by John Shearer/Getty Images for MTV)

People walk behind the Medusa head in the Basilica Cistern in Istanbul, Turkey, 24 July 2022. The site has been restored by the Istanbul Metropolitan Municipality and is now open for visitors again. The Byzantine structure was commissioned by Emperor Justinian and built in 532. The underground Basilica, also called Underground Cistern, is the largest well preserved cistern in Istanbul, which rests on a total of 336 columns. According to historical texts, more than 7,000 slaves were involved in the construction of the cistern. (Photo by Sedat Suna/EPA/EFE)

“Dover Castle is a medieval castle in the town of the same name in the English county of Kent. It was founded in the 12th century and has been described as the “Key to England” due to its defensive significance throughout history. It is the largest castle in England.

The outbreak of the Second World War in 1939 saw the tunnels converted first into an air-raid shelter and then later into a military command centre and underground hospital. In May 1940, Admiral Sir Bertram Ramsey directed the evacuation of French and British soldiers from Dunkirk, code-named Operation Dynamo, from his headquarters in the cliff tunnels”. – Wikipedia

Photo: The Repeater Station in the subterranean tunnels underneath Dover Castle, which has been restored by English Heritage for a public exhibition on June 3, 2011 in Dover, England. The evacuation of allied soldiers from Dunkirk was masterminded and co-ordinated from the secret command and control centre in the tunnels deep below the castle. (Photo by Matthew Lloyd/Getty Images)

Yueyaquan is a crescent-shaped lake in an oasis, 6 km south of the city of Dunhuang in Gansu Province, China. It was named Yueyaquan in the Qing Dynasty. According to measurements made in 1960, the average depth of the lake was 4 to 5 meters, with a maximum depth of 7.5 metres In the following 40 years, the depth of the lake continually declined. In the early 1990s, its area had shrunk to only 5,500 m2 with an average depth of 0.9 meter (maximum 1.3 meter). In 2006, the local government with help of the central government started to fill the lake and restore its depth; its depth and size have been growing yearly since then. The lake and the surrounding deserts are very popular with tourists, who are offered camel and 4x4 rides.