A hot air balloon rises in the sky during the International Hot-Air Balloon festival in Pokhara on December 27, 2024. With Nepal's snowy Himalayan peaks as a backdrop, the sky above Pokhara transformed into a vibrant canvas of colours for the country's first hot-air balloon festival. (Photo by Prakash Mathema/AFP Photo)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

A volunteer holds the peak of a flamingo chick after it was fitted with an identity ring at a lagoon in the Fuente de Piedra natural reserve near Malaga, southern Spain, July 30, 2022. (Photo by Jon Nazca/Reuters)

This aerial image shows autumn leaves at their peak as they surround Tsutenkyo Bridge amongst the grounds of Tofukuji Temple, in the city of Kyoto on November 27, 2024. (Photo by JIJI Press/AFP Photo)

Buzludzha is a historical peak in the Central Stara Planina, Bulgaria and is 1441 metres high. In 1868 it was the place of the final battle between Bulgarian rebels led by Hadji Dimitar and Stefan Karadzha and the Ottoman Empire. The Buzludzha Monument on the peak was built by the Bulgarian communist regime to commemorate the events in 1891 when the socialists led by Dimitar Blagoev assembled secretly in the area to form an organised socialist movement with the founding of the Bulgarian Social Democratic Party, a fore-runner of the Bulgarian Communist Party. The Monument was opened in 1981. No longer maintained by the Bulgarian government, it has fallen into disuse. Buzludzha is reached by a 12 km side road from the Shipka Pass.

Lily Nguyen of Jessop, from Maryland, leaps up in the air as a friend takes her photo in front of cherry blossoms which have reached their peak bloom, along the Tidal Basin, in Washington, D.C., U.S., March 21, 2022. (Photo by Kevin Lamarque/Reuters)

A man wearing a hazmat suit and a mask holds a sign reading “The end is near – call grandma” at Times Square on March 14, 2020 in New York City. The World Health Organization said March 13, 2020 it was not yet possible to say when the COVID-19 pandemic, which has killed more than 5,000 people worldwide, will peak. “It's impossible for us to say when this will peak globally”, Maria Van Kerkhove, who heads the WHO's emerging diseases unit, told a virtual press conference, adding that “we hope that it is sooner rather than later”. (Photo by Johannes Eisele/AFP Photo)

Graduates dance as they take part in a “Last school bell” ceremony at a school in Minsk, Belarus on May 30, 2018. (Photo by Vasily Fedosenko/Reuters)