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)

Myanmar punks walk in the downtown area as they take part in a punk gathering ahead of the Thingyan water festival in Yangon, Myanmar, 12 April 2017. Myanmar punks have been gathering in Yangon on the day ahead of Thingyan water festival to celebrate every year. The annual water festival is marked with large groups of people congregating to celebrate by splashing water and throwing powder at each others faces as a symbolic sign of cleansing and washing away the sins from the old year to mark the traditional New Year in countries such as Myanmar, Thailand, Laos and Cambodia. This year, the Myanmar Thingyan water festival falls on 13 April and ends on 16 April. (Photo by Lynn Bo Bo/EPA)

The Viking longboat burns during the annual Up Helly Aa festival in Lerwick, Shetland Islands, on January 28, 2014. Up Helly Aa celebrates the influence of the Scandinavian Vikings in the Shetland Islands and culminates with up to 1,000 “guizers” (men in costume) throwing flaming torches into their Viking longboat and setting it alight later in the evening. (Photo by Andy Buchanan/AFP Photo via Getty Images)

Thousands of heavy-duty trucks loaded with coal are lined up for up to 130 kilometres from the Mongolia-China border on a sole road in the Gobi desert, Mongolia, October 29, 2017. The journey can take more than a week. (Photo by Bazarsukh Rentsendorj/Reuters)

Miss Bunni Lambada poses backstage during the Miss Pin Up NSW competition on October 23, 2010 in Sydney, Australia. Pinup girls from across New South Wales descended on The Entrance to compete in the state competition with hopes to represent NSW at the inaugural Miss Pin Up Australia national competition in January 2011. (Photo by Lisa Maree Williams/Getty Images)

People celebrate the traditional Fiesta de las Aguedas on February 6, 2022 in Andavias, Zamora, Castilla y Leon, Spain. This celebration, also known as “El dia de las mujeres”, is a deep-rooted tradition in Castilla y Leon, especially in rural areas. The day of the Aguedas has its origin in the cult of Santa Agueda, and is celebrated every February 5. (Photo By Emilio Fraile/Europa Press via Getty Images)

It's taken roughly five months, but a massive iceberg has separated from Antarctica's Pine Island Glacier. According to NASA's Earth Observatory, the estimated size of this iceberg, named B-31, is around 660 square kilometres (33 km long by 20 km wide) – a city-sized block of ice that has slowly migrated away from the continent, and is now floating out to sea. Take a look at some massive icebergs afloat in the oceans. Photo: File photo of an iceberg floating near a harbour in the town of Kulusuk, east Greenland August 1, 2009. (Photo by Bob Strong/Reuters)