A pupil of the Dao ethnic tribe returns home from school along a hillside path at Suoi Thau village in Hoang Su Phi district of Vietnam's northern province of Ha Giang, located at the border with China, September 18, 2015. (Photo by Reuters/Kham)

Vietnam’s Son Doong cave, the largest in the world, could hold a 40-story skyscraper inside. The pristine ecosystem has its own river and jungle. Despite its size, Son Doong wasn’t discovered until 1991. It was lost again for nearly two decades and was fully explored for the first time in 2009. (Photo by Jason Speth/HuffPost)

A Vietnamese woman, wearing the traditional “ao dai” long dress, poses for photos along peach blossom flowers ahead of the Vietnamese “Tet” (Lunar New Year festival), in a field in Hanoi, Vietnam, February 2, 2016. (Photo by Reuters/Kham)

Two hippopotamus are fed with pumpkins at the Hanoi Zoo, in Hanoi, Vietnam, 25 October 2018. The zoo has been the home for more than 800 animals of over 90 different species, including three hippopotamus, since it was built in 1976. (Photo by Luong Thai Linh/EPA/EFE)

A Vietnamese cosplayer poses as police officer character from the game during the League of Legends (LOL) Mid-Season Invitational 2019 play-in group stage, in GG Stadium, Ho Chi Minh, Vietnam May 5, 2019. (Photo by Reuters/Kham)

Schoolchildren play music to entertain and inspire people on their way home from work Tuesday, March 29, 2016 in Pyongyang, North Korea. North Korea has called a 70-day loyalty drive areas of a major congress of the ruling party scheduled for early May and everyone from students to coal miners have been mobilized nationwide to demonstrate their devotion to the leadership. (Photo by Eric Talmadge/AP Photo)

A journalist reports on a ladder outside the Great Hall of the People during the opening session of the National People's Congress (NPC) in Beijing, China March 5, 2018. The NPC has over 3,000 delegates and is the world's largest parliament or legislative assembly though its function is largely as a formal seal of approval for the policies fixed by the leaders of the Chinese Communist Party. The NPC runs alongside the annual plenary meetings of the Chinese People's Political Consultative Conference (CPPCC), together known as “Lianghui” or “Two Meetings”. (Photo by Thomas Peter/Reuters)

Local folk artists perform next to a police line outside Congress building, as they wait for news from inside on who will be the country's next president, in Lima, Peru, Sunday, November 15, 2020. Interim President Manuel Merino announced his resignation following massive protests unleashed when lawmakers ousted President Martin Vizcarra. (Photo by Rodrigo Abd/AP Photo)