Youth category winner: Symphony No 5 by Giacomo Redaelli (Italy). (Photo by Giacomo Redaelli/2019 Nature Photographer of the Year)

Tribesmen loyal to the Houthi movement perform the Baraa dance during a gathering to show support to the movement in Sanaa, Yemen, May 19, 2016. Bara or Baraa dance is one of the several traditional outdoor dances performed by men in the country of Yemen. Bara dance literally means a dagger dance, where each dancer holds a dagger. The style of the Bara dance differs from tribe to tribe. It is performed on special occasions. (Photo by Khaled Abdullah/Reuters)

A Nepalese Hindu boy in festival attire walks in a procession during “Gai Jatra”, or Cow Festival in Kathmandu, Nepal, Friday, August 19, 2016. Members of Nepal's Newar Community celebrate the festival in memory of their family members who died the preceding year, believing that the cow will guide them in their journey to heaven. (Photo by Niranjan Shrestha/AP Photo)

A girl looks with comic disgust at a guy who falls asleep with a bottle of beer at a party; her friend laughs. (Photo by Edward Corbett/Rex Features/Shutterstock)

An orphaned rhesus monkey and white dove that seemed to have lost its mate forged a special bond at the Neilingding Island-Futian National Nature Reserve in China. The monkey was born on the island but had strayed from its mother. Luckily, it was taken in by work staff in the protection center and became friends with the pigeon that had lingered there after possibly losing its mate. (Photo by CNImaging/Photoshot)

Mara Salvatrucha (MS) gang members show off their weapons in the Las Victorias district of San Salvador. In March 2012, the two largest gangs in El Salvador - the Mara Salvatrucha (MS) and the Barrio 18 (M18) - agreed on a truce following secret negotiations between gang leaders in prison which were mediated by a bishop and a former rebel leader. It is unclear whether the decision was the idea of the gangs themselves or whether they were encouraged by the government. (Photo by Adam Hinton)

A BASE jumper is pictured against the skyline shrouded in a thick haze during the Kuala Lumpur Tower International Jump in Kuala Lumpur, Malaysia, 02 October 2015. More than 100 BASE jumpers take part in this extreme sport event, which enters its 15th year. The haze hovering over Malaysia is caused by the ongoing plantation and forest fires in the nearby Indonesian provinces of Sumatra and Kalimantan. (Photo by Fazry Ismail/EPA)

The Komodo dragon (Varanus komodoensis) was the most popular species overall based on English language Wikipedia page views. It is the world’s largest lizard, living on the islands of Komodo, Rinca and other smaller islands, and on Flores island in Indonesia. (Photo by Eric Nathan/Alamy)