A Member of the Congress of South African Trade Unions (COSATU) joins other strikers as they take part in a nationwide strike over issues including corruption and job losses outside parliament in Johannesburg, South Africa, October 7, 2020. (Photo by Siphiwe Sibeko/Reuters)

In this photo taken Wednesday, March 8, 2017, a hospitality staff member pose for photos near the shadow of a tall light pole near the Great Hall of the People where a plenary session of the National People's Congress is held in Beijing, China. (Photo by Ng Han Guan/AP Photo)

Bus ushers leap as they pose for a group photo during a meeting one day ahead of the opening session of China's National People's Congress (NPC) at the Great Hall of the People in Beijing, Monday, March 4, 2019. (Photo by Mark Schiefelbein/AP Photo)

Attendants wait for visitors to the the exhibition entitled “Forging Ahead in the New Era”, showing the country's achievements during his past two terms, at the Beijing Exhibition Center in Beijing on October 12, 2022, ahead of the 20th Communist Party Congress meeting. (Photo by Noel Celis/AFP Photo)

Bus hostesses adjusts their hair before photos outside the Great Hall of the People the eve of the opening session of the annual meeting of China's National People's Congress (NPC) in Beijing, Saturday, March 4, 2023. (Photo by Ng Han Guan/AP Photo)

Friends and family fuss over a quinceañera in preparation for her photo session at Colon square in the Zona Colonial neighborhood of Santo Domingo, Dominican Republic, Wednesday, May 15, 2024. Dominicans head to the polls on Sunday, May 19th to elect a new president and members of their Congress. (Photo by Matias Delacroix/AP Photo)

Son doong cave is a cave in Phong Nha-Kẻ Bàng National Park, Bố Trạch district, Quảng Bình Province, Vietnam. Currently the biggest known cave in the world, the cave is located near the Laos-Vietnam border. Inside is a large, fast-flowing underground river.
In early August 2013, the first tourist group explored the cave on a guided tour at a cost of US$3,000 each. The group had six members from Australia, Norway, Russia and USA and spent 7 days and 6 nights for the tour. Next exploration trips will be arranged.

Runner-up; Hon Yen marine ecosystem. Phu Yen, Vietnam. Every year between May and August, the coral of this rich and diverse ecosystem becomes exposed at low tide. (Photo by Truong Hoai Vu/Royal Society of Biology Photography Competition)