A huge colony of Pacific Walrus on Arakamchechen Island in the Northern Bering Sea. (Photo by Francois Gohier/Ardea/Caters News)

“Unexpected humour”. The Dog and the Faucet, in Kolkata, India on January 2017. (Photo by Pau Buscató/The Guardian)

Singer Rita Ora enters her hotel on April 27, 2017 in New York City. (Photo by MEGA)

A 12th century manuscript of The Old Testament sits in the Chained Library of Hereford Cathedral after it's annual spring clean on January 24, 2012 in Hereford, England. (Photo by Christopher Furlong/Getty Images)

Keira Knightly attends the UK Gala Premiere of “A Dangerous Method” at The Mayfair Hotel on January 31, 2012 in London, England. (Photo by Stuart Wilson/Getty Images)

An unexpected side-effect of the flooding in parts of Pakistan has been that millions of spiders climbed up into the trees to escape the rising flood waters. Because of the scale of the flooding and the fact that the water has taken so long to recede, many trees have become cocooned in spiders’ webs.

Beautiful, strange and occasionally alarming pictures from the shortlist for this year’s Wellcome image awards – which celebrate the very best in science photography and imaging – from an x-ray of a bat to a micrograph of a kidney stone. The exhibition opens on 12 March at three science centres and the Museum of Science and Industry in Manchester. Photo: Scanning electron micrograph (SEM) of an Arabidopsis thaliana flower, also commonly known as thale cress. Some of the anthers are open, revealing pollen grains ready for dispersal. Arabidopsis was the first plant to have its entire genome sequenced and is widely used as a model organism in molecular and plant biology. Horizontal width of image is 1200 microns. Magnification 100x. (Photo by Stefan Eberhard/Wellcome Images)

An art installation formed with milk churns, made by land art artist Gerard Benoit a la Guillaume, is seen at the Chenau de Mayen in the resort of Leysin, Switzerland August 7, 2015. More than 80 milk churns were placed between the Tour d'Ai and the Tour de Mayen summits at an altitude of 2,000 meters (6,561 feet) above sea level under the direction of the artist, to be photographed for his ongoing art project entitled “Milk churns without borders”. (Photo by Denis Balibouse/Reuters)