Participant wearing medieval costumes perform during an annual re-enactment of a battle near the village of Libusin, Czech Republic, April 23, 2016. About 2000 enthusiasts have come to simulate the medieval battle during the 24rd annual swordsmen gathering in Libusin village. (Photo by David W. Cerny/Reuters)

Aleksandra Krunic, of Serbia, drops to the court after defeating Petra Kvitova, of the Czech Republic, during the third round of the 2014 U.S. Open tennis tournament, Saturday, August 30, 2014, in New York. (Photo by Kathy Willens/AP Photo)

Participants in fancy costumes take part in march during the Prague Pride parade in downtown Prague, Czech Republic, 10 August 2019. Several thousands of people attended the 9th Prague Pride to support the LGBT (lesbian, gay, bisexual and transgender) communities. (Photo by Martin Divisek/EPA/EFE/Rex Features/Shutterstock)

Participants dressed as characters such as elves, dwarves, goblins and orcs from the J.R.R. Tolkien's novel “The Hobbit” re-enact the “Battle of Five Armies” in a forest near the town of Doksy, Czech Republic, June 4, 2016. Several hundred people arrived in the forest to re-enact the famous battle from Tolkien's novel that was published for the first time in 1937. (Photo by David W. Cerny/Reuters)

Switzerland's Belinda Bencic celebrates after defeating Czech Republic's Marketa Vondrousova during their Tokyo 2020 Olympic Games women's singles tennis final match at the Ariake Tennis Park in Tokyo on July 31, 2021. (Photo by Yara Nardi/Reuters)

Greece's Apostolos Angelis (L) and Austria's Felix Leitner compete during the men's 20 km individual event of the IBU Biathlon World Championships in Nove Mesto, Czech Republic on February 14, 2024. (Photo by Joe Klamar/AFP Photo)

Members of the contemporary circus company Cirk La Putyka perform in front of sculpture of Franz Kafka's head to entertain local residents in Prague, Czech Republic, 21 April 2020. The aim of the Cirk La Putyka events in the streets of Czech capital is to get live art back to people during the lockdown. According to them, when people can't go to the artists, to the theater, the actors go to the people. The Czech government has imposed a lockdown in an attempt to slow down the spread of the pandemic COVID-19 disease caused by the SARS-CoV-2 coronavirus. (Photo by Martin Divisek/EPA/EFE/Rex Features/Shutterstock)

The Prague astronomical clock, or Prague orloj, is a medieval astronomical clock located in Prague, the capital of the Czech Republic. The clock was first installed in 1410, making it the third-oldest astronomical clock in the world and the oldest one still working.