The full moon, known as the Blue Moon, is seen over Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen behind a running train on the Sydney Harbour Bridge in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen behind the Telstra Tower on the Black Mountain in Canberra, Australia, on May 31, 2026. (Xinhua/Chu Chen)

The full moon, known as the Blue Moon, is seen behind a running train on the Sydney Harbour Bridge in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen over Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen behind the Telstra Tower on the Black Mountain in Canberra, Australia, on May 31, 2026. (Xinhua/Chu Chen)

The full moon, known as the Blue Moon, is seen over Sydney Opera House in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen behind a running train on the Sydney Harbour Bridge in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen behind the Telstra Tower on the Black Mountain in Canberra, Australia, on May 31, 2026. (Xinhua/Chu Chen)

The full moon, known as the Blue Moon, is seen behind the Sydney Harbour Bridge in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen over Sydney Opera House in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen over Sydney Opera House in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)

The full moon, known as the Blue Moon, is seen over Canberra, Australia, on May 31, 2026. (Xinhua/Chu Chen)

The full moon, known as the Blue Moon, is seen over Sydney Opera House in Sydney, Australia, on May 31, 2026. (Xinhua/Gong Bing)