The last of the summer roses are dusted with a coating of frost as the first freezing temperatures descend on Britain on November 7, 2011 in Knutsford, England. The roses are the last blooms to survive the Summer at Curbishleys specialist rose nursery in Cheshire. (Photo by Christopher Furlong/Getty Images)

Vietnamese military personnel in traditional dress take part in a parade celebrating the 40th anniversary of the end of the Vietnam War which is also remembered as the fall of Saigon, in Ho Chi Minh City, Vietnam, Thursday, April 30, 2015. (Photo by Dita Alangkara/AP Photo)

Vietnamese female commissioned officers of the signal force march during a parade marking their 70th National Day at Ba Dinh square in Hanoi, Vietnam September 2, 2015. (Photo by Reuters/Kham)

A labourer packs incense in preparation for Tet, the traditional Vietnamese lunar new year, in Hong Chau village, outside Hanoi January 29, 2015. Tet is from February 14 till 24. (Photo by Reuters/Kham)

Children wave Vietnamese and American flags while waiting for arrival of U.S. President Barack Obama (not pictured) before a welcoming ceremony at the Presidential Palace in Hanoi, Vietnam May 23, 2016. (Photo by Reuters/Kham)

This photograph taken on June 8, 2021 shows a street vendor walking past narrow residential houses, known as “nha ong” in Vietnamese or “tube houses”, in an urban area of Hanoi. (Photo by Manan Vatsyayana/AFP Photo)

A woman collects lotus flowers at a lake in Hanoi, Vietnam, 20 June 2018. Lotus flowers, that bloom every June, are collected by Vietnamese people for their inner parts to be mixed with tea for fragrance. (Photo by Luong Thai Linh/EPA/EFE)

People wear clothing to protect them from the heat while riding along a street in Hanoi, Vietnam, 24 April 2019. North and central Vietnam was recently affected by extreme hot weather, with the highest temperatures reaching over 40 degrees Celcius, according to the National Centre for Hydro-meteorological Forecasting. (Photo by Luong Thai Linh/EPA/EFE)