Photo taken on May 20, 2022 shows a view of the Hoa Lu Ancient Town in northern Vietnam's Ninh Binh province. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Photo taken on May 20, 2022 shows a view of the Hoa Lu Ancient Town in northern Vietnam's Ninh Binh province. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Tourists take boats to travel across the Tam Coc-Bich Dong scenic area in northern Vietnam's Ninh Binh province, May 21, 2022. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Tourists travel around the Tam Coc-Bich Dong scenic area in northern Vietnam's Ninh Binh province, May 21, 2022. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Tourists take boats to travel across the Tam Coc-Bich Dong scenic area in northern Vietnam's Ninh Binh province, May 21, 2022. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Photo taken on May 20, 2022 shows a view of the Hoa Lu Ancient Town in northern Vietnam's Ninh Binh province. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Tourists take boats to travel across the Tam Coc-Bich Dong scenic area in northern Vietnam's Ninh Binh province, May 21, 2022. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)

Photo taken on May 20, 2022 shows a view of the Hoa Lu Ancient Town in northern Vietnam's Ninh Binh province. The province is hosting the 2022 Ninh Binh Tourism Week from May 21 to 28. (Xinhua/Jiang Shengxiong)