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)

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)

“Miniatur Wunderland is a model railway attraction in Hamburg, Germany and the largest of its kind in the world. As of January 2011, the railway consists of 12,000 metres (39,370 ft) of track in HO scale, divided into seven sections: Harz, the fictitious city of Knuffingen, the Alps and Austria, Hamburg, America, Scandinavia, and Switzerland. Of the 6,400 square metres (68,889 sq ft) of floorspace, the model takes 1,150 m2 (12,378 sq ft)”. – Wikipedia

Photo: Details of the “Miniatur Wunderland” are pictured on April 2, 2009 in Hamburg, Germany. The world's largest model railway and one of the most popular tourist attractions in Germany is located next to the Elbe in Hamburg's Speicherstadt. (Photo by Joern Pollex/Getty Images)

Brazilian singer Anitta performs during the “Ensaios de Anitta” show, an event that is part of a pre-carnival tour that makes its way through several Brazilian cities, paying tribute to a samba school in each performance at the Jockey Club of Rio de Janeiro, Brazil, 21 January 2024. Anitta only performs this time of year in her country and said that experiencing a carnival is the best way to get to know the Brazilian people because all the energy of its people is concentrated on a single topic. (Photo by Andre Coelho/EPA/EFE)

Miniature spring-wound 35-mm film camera in a modified cigarette pack. The Tessina’s small size and quiet operation provided more options for concealment than most commercially available models. (Photo by Central Intelligence Agency)

Traders lay out their stools in a fishing village of Long Hai commune in Vung Tau province, Vietnam on June 17, 2020 with the market opening at midnight and trading into the early hours of the morning each day. It is the largest wholesale fishing market in the region and market traders can be seen sorting their fish into their different types before putting them into different coloured boxes for sale. (Photo by Pham Huy Trung/Solent News)

The Dragon Bridge (Vietnamese: Cầu Rồng) is a bridge over the River Hàn at Da Nang, Vietnam. Construction of the bridge began on 19 July 2009 (the same day as the inauguration of the nearby Thuận Phước Bridge) when the Prime Minister of Vietnam Nguyen Tan Dung and many high-ranking government officials attended the groundbreaking ceremony. Dragon Bridge is 666m long, 37.5m wide and has six lanes for traffic. It opened to traffic on March 29, 2013, at a cost os nearly VND 1.5 trillion dong (US$88m). The bridge was designed by the US-based Ammann & Whitney Consulting Engineers with Louis Berger Group. Construction was undertaken by Company No. 508, an affiliate of Civil Construction Engineering Corporation No.5, and Bridge Company No. 75.

Laos, officially the Lao People's Democratic Republic, is a landlocked country in Southeast Asia, bordered by Burma and China to the northwest, Vietnam to the east, Cambodia to the south, and Thailand to the west. Its population was estimated to be around 6.5 million in 2012. A third (33%) of the country's population lives below the international poverty line which means living on less than U.S. $1.25 per day.