An alien-themed balloon installation is seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A visitor takes photos of dolphin-themed balloon installations during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A woman takes photos of a child during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A marine life-themed balloon installation is seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A fish-themed balloon installation is seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

Visitors view underwater world-themed balloon installations during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

People pose for photos during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

Penguin-themed balloon installations are seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A crab-themed balloon installation is seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A visitor takes pictures of marine life-themed balloon installations during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A woman poses for photos during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

A tiger-themed balloon installation is seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)

Marine life-themed balloon installations are seen during the World Balloon Festival in Warsaw, Poland, May 15, 2026. The festival takes place here from May 15 to 17, featuring large themed installations featuring tropical jungles, underwater world, outer space and architectural landmarks created with more than 100,000 biodegradable balloons. (Photo by Jaap Arriens/Xinhua)