Fabrice Monteiro travelled to the most polluted places in Africa and created terrifying characters who roamed their midst dressed in eerie debris. They are spirits, he says, on a mission to make humans change their ways. Informed by Africa’s environmental problems, Fabrice Monteiro’s photographs aim to highlight urgent ecological issues all over the world. His series “The Prophecy” is on show at Photo Basel 2017 until 18 June. (Photo by Fabrice Monteiro/Photo Basel 2017/Mariane Ibrahim Gallery/The Guardian)

“Cassowaries are large, flightless birds related to emus and (more distantly) to ostriches, rheas, and kiwis”, writes Olivia Judson in the September issue of National Geographic magazine. How large? People-size: Adult males stand well over five foot five and top 110 pounds. Females are even taller, and can weigh more than 160 pounds. Dangerous when roused, they’re shy and peaceable when left alone. But even birds this big and tough are prey to habitat loss. The dense New Guinea and Australia rain forests where they live have dwindled. Today cassowaries might number 1,500 to 2,000. And because they help shape those same forests – by moving seeds from one place to another – “if they vanish”, Judson writes, “the structure of the forest would gradually change” too. (Photo by Christian Ziegler/National Geographic)

Handout grab taken from YouTube of Commander Chris Hadfield who has said goodbye to life on the International Space Station by making a cover version of David Bowie's Space Oddity. Issue date: Monday May 13, 2013. (Photo by Commander Chris Hadfield/YouTube/PA Wire)

National Geographic photographer Steve Winter has spent most of his adult life shooting wild cats. Photo: A 14-month-old cub, cooling off in a pond, is riveted by a deer that appeared near the shore. Tigers are powerful swimmers; they can easily cross rivers four to five miles wide and have been known to swim distances of up to 18 miles. (Photo by Steve Winter/National Geographic)

South Korean police officers show their martial arts' skills during the official launch ceremony of the 2012 Seoul Nuclear Security Summit on February 15, 2012 in Seoul, South Korea. The Korean National Police Agency launched a security squad, exclusively established for the successful hosting of the 2012 Seoul Nuclear Security Summit. The 2012 Seoul Nuclear Security Summit will be held in Seoul from March 26-27, 2012. (Photo by Chung Sung-Jun/Getty Images)

These spectacular images of the universe are the finalists in the 2016 CWAS “David Malin” awards. The annual competition, which celebrates the best astronomy images taken by Australian photographers, is part of AstroFest 2016. The winners will be announced on 16 July. An associated exhibition opens the following day at the CSIRO Parkes Observatory visitors centre, and a second exhibition will also travel to selected venues around Australia. Here: Mars and its Rival Antares and the Rho Ophiuchi cloud complex. (Photo by Phil Hart/CWAS/The Guardian)