Cambridge policemen, known as “Bulldogs”, lined up for the University Bulldogs Chase, dressed in morning coats and top hats, 7th March 1936. (Photo by H. Allen/Topical Press Agency/Getty Images)

Indian Naga Sadhus, or naked holy men, participate in a procession before taking a “shahi snans”, or holy bath, at the Sangam river, the confluence of three of the holiest rivers in Hindu mythology, the Ganga, the Yamuna and the Saraswati, during Kumbh Mela festival in Allahabad, Uttar Pradesh, India, 15 January 2019. The Hindu festival is one of the biggest in India and will be held from 15 January to 04 March 2019 in Allahabad. (Photo by Rajat Gupta/EPA/EFE)

Londoners enjoy a “Silent Night” as Big Ben falls silent, London, UK on August 21, 2017. ose Allerston from Clapham, London said “After a stressful day in the office, I couldn't think of anything better than going home and climbing into bed – but when I saw this bed opposite Big Ben I just couldn't resist getting in for a snuggle”. (Photo by Imagewise Ltd/Rex Features/Shutterstock)

This image of a young bareback rider was taken in the village of Palenque de San Basilio, in Colombia’s Bolívar department. Founded by freed slaves in the 17th century, it became the first free town in the Americas, following a decree by the Spanish crown. Most of today’s inhabitants are direct descendants of those slaves and have preserved many of their customs, including their own language, Palenquero. (Photo by Sebastián Suki Beláustegui/The Guardian)

A Boeing 777-300 from Swiss International Airlines lands on a foggy morning at Zurich Airport, on Friday, October 13, 2017, in Zurich, Switzerland. The high humidity renders the air vortex visible. (Photo by Christian Merz/Keystone via AP Photo)

Behaviour: Mammals category. Giant Gathering by Tony Wu, USA. Dozens of sperm whales mingled noisily off Sri Lanka’s northeast coast, stacked as far down as Tony could see. This was a congregation of dozens of social units, like a gathering of the clans. Aggregations like this could be a critical part of the whales’ rich social lives but are rarely reported. Some two thirds of the population was wiped out before commercial whaling was banned in 1986. This kind of major gathering could be “a sign that populations are recovering”, says Tony. (Photo by Tony Wu/Wildlife Photographer of the Year 2017)

Bride Katty Malang Mikunug with friends, takes a photo before the wedding on October 21, 2017 in Saguiaran in Lanao del Sur, southern Philippines. Paulo Mamayo Ambor, 22, a resident of Marawi who got displaced by the fighting between government troops and IS-inspired militants, weds Katty Malang Mikunug, 22, a resident of an adjacent town in Saguiaran. Philippines President Rodrigo Duterte declared Marawi liberated, following the death of Abu Sayyaf leader Isnilon Hapilon and one of the Maute brothers, Omar Maute, after nearly five months of fierce urban battle inside the besieged city. The fighting started May 23, and left more than 1,000 people dead, whilst displacing at least 400,000 people. (Photo by Jes Aznar/Getty Images)

Rescuers attempt attempt to push stranded whales back into the ocean at Ujong Kareng beach in Aceh province, Indonesia, Monday, November 13, 2017. An official said a small pod of whales was stranded at the beach and attracted hundreds of onlookers who posed for pictures with them. (Photo by AP Photo/Zulkarnaini)