A new book published by the UK Natural History Museum showcases some of the most memorable underwater photographs taken over the last few decades in its annual wildlife photographer of the year competition. Here: Giant gathering by Tony Wu. “The first indication that something extraordinary was going on were the blows, huge numbers of them – the exhalations of huge numbers of whales. Entering the water, the photographer witnessed an extraordinary scene”. (Photo by Tony Wu/Unforgettable Underwater Photography/NHM)

These black-and-white photos are taken from the new book “Armoured Warfare in the First World War 1916 – 1918” by Anthony Tucker-Jones and published by Pen & Sword Military. Here: British troops hitch a ride on a Mark IV after the massed tank fleet spearheading attack at Cambrai on November 20, 1917. (Photo by Anthony Tucker-Jones/Mediadrumworld.com)

A woman sweeps an alleyway adorned with murals painted by artists from “Delhi Street Art” group at the Raghubir Nagar slum in New Delhi on December 2, 2019. A New Delhi slum has been given a colourful makeover thanks to a street artist collective, drawing art lovers and selfie-snappers to a rundown area that they would never normally visit. (Photo by Sajjad Hussain/AFP Photo)

Alex Prager is an American art photographer and filmmaker based in Los Angeles. Her photographs primarily use staged actors, models and extras to create “meticulously designed mise en scène”, often described as film-like and hyperreal. “Alex Prager: Silver Lake Drive” is at the Photographers’ Gallery, London, 15 June – 14 October 2018. Here: The Big Valley, Susie and Friends, 2008. (Photo by Alex Prager Studio/Lehmann Maupin Gallery)

Moraine Lake is a glacially-fed lake in Banff National Park, 14 kilometres (8.7 mi) outside the Village of Lake Louise, Alberta, Canada. It is situated in the Valley of the Ten Peaks, at an elevation of approximately 6,183 feet (1,885 m). The lake has a surface area of .5 square kilometres (0.19 sq mi). The lake, being glacially fed, does not reach its crest until mid to late June. When it is full, it reflects a distinct shade of blue. The colour is due to the refraction of light off the rock flour deposited in the lake on a continual basis.

Tibetan monks create an intricate picture made from coloured sand at St. Mungo Museum of Religious Life and Art on November 23, 2011 in Glasgow, Scotland. The monks, from the Panchen Lama's Monastery, are creating a Sand Mandala as part of a Tantric Buddhist ritual, invoking the presence of the Buddha in a design representing the palace of the deities. (Photo by Jeff J Mitchell/Getty Images)

In 1994, after the fall of the Soviet Union, all Ukrainians had to get a new passport – and photographer Alexander Chekmenev was on hand to take their photos. The snatched extra shots he took are remarkable in their honesty and tenderness. (Photo by Alexander Chekmenev/The Guardian)

Luis Hernan was always curious about how wireless technologies like radio are transmitted through the air. So after finishing up his studies in architecture, computer science, and design, Hernan decided to research these invisible signals through a PhD at Newcastle University. Hernan set up a system that turned the wireless signals around him into colourful, ghostlike images using long-exposure photography, allowing people to see the strength of the signals around them. (Photo by Luis Hernan)