Helicopters fly with Singapore's national flag during the National Day celebrations in Singapore, Aug. 9, 2021. Singapore celebrated the 56th anniversary of independence on Monday. (Photo: Xinhua)

Helicopters fly with Singapore's national flag during the National Day celebrations in Singapore, Aug. 9, 2021. Singapore celebrated the 56th anniversary of independence on Monday. (Photo: Xinhua)

A fleet of fighter planes flies in formation during the National Day celebrations in Singapore, Aug. 9, 2021. Singapore celebrated the 56th anniversary of independence on Monday. (Photo: Xinhua)

A fleet of fighter planes flies in formation during the National Day celebrations in Singapore, Aug. 9, 2021. Singapore celebrated the 56th anniversary of independence on Monday. (Photo: Xinhua)

Helicopters fly with Singapore's national flag during the National Day celebrations in Singapore, Aug. 9, 2021. Singapore celebrated the 56th anniversary of independence on Monday. (Photo: Xinhua)