Tactics reminiscent of the early American frontier days are now being used in Vietnam. Lieutenant Commander Donald D. Sheppard, UBN, of Coronado, California, aims a flaming arrow at a bamboo hut concealing a fortified Viet Cong bunker on the banks of the Bassac River, Vietnam on December 8, 1967. (Photo by AP Photo)

Anti-pollution protesters wearing traditional costumes and contemporary gas masks ride bicycles in the Qingming Grand river park in Kaifeng, Henan Province, China on January 1, 2017. The Beijing Municipal Environmental Protection Bureau extended an “orange alert” for heavy air pollution for three more days. (Photo by SIPA Asia/Rex Features/Shutterstock)

A member of the “Bloco Ultima Hora” group gets off a boat during Carnival of the Waters, where costumed and colorful boats navigate the river Tentem, around the islands near the city of Cameta, Brazil on February 8, 2018. (Photo by Ueslei Marcelino/Reuters)

An aerial view shows a Russian Troika, a sledge drawn by three horses, competing on the ice-covered Yenisei River during the annual Ice Derby amateur horse race near the Siberian settlement of Novosyolovo, south of Krasnoyarsk, Russia March 17, 2018. (Photo by Ilya Naymushin/Reuters)

A man tries to catch a duck during a competition held as a part of the Dragon Boat Festival, known locally as “Peh Cun Festival”, on the Cisadane river in Tanggerang, Indonesia, Thursday, June 9, 2016. The event is celebrated every fifth day of the fifth month on the Chinese lunar calendar. (Photo by Tatan Syuflana/AP Photo)

A girl catches a fish in the marshes of the southern district of Chibayish in Dhi Qar province, about 120 kilometres northwest of the southern city of Basra, on September 23, 2020. Iraq's southern marshes are blossoming thanks to a wave of ecotourists picnicking and paddling down their replenished river bends. (Photo by Hussein Faleh/AFP Photo)

Aerial view of contestants attending the opening ceremony of a dragon boat race on the Rongjiang River at Rong'an County on October 10, 2020 in Liuzhou, Guangxi Zhuang Autonomous Region of China. (Photo by Tan Kaixing/VCG via Getty Images)

A Hindu devotee lies on the banks of river Ganges she worships the Sun god during the religious festival of Chhath Puja, amidst the spread of the coronavirus disease (COVID-19), in Kolkata, India on November 20, 2020. (Photo by Rupak De Chowdhuri/Reuters)