The Observer's 20 photographs of the week

A Syrian refugee girl behind a fence at a shelter for migrants near Lyubimets in Bulgaria Photograph: Dimitar Dilkoff/AFP/Getty Images

England's Ian Bell dives to make his ground during play on the fifth day of the fifth Ashes Test match between England and Australia at The Oval cricket ground in London Photograph: Glyn Kirk/AFP/Getty Images

A Free Syrian Army fighter walks past a torn poster amid the rubble in the old city of Aleppo Photograph: Muzaffar Salman/Reuters

A boy holds a poster of Syria's President Bashar al-Assad during a demonstration against potential strikes on the Syrian government, in Sana'a Photograph: Khaled Abdullah/Reuters

A man climbs outside a window with a knife, as his mother and a plainclothes policeman look on, in Anshan, Liaoning province, in China Photograph: China Stringer Network/Reuters

A man runs up the 'gostra', a pole covered in grease, during the religious feast of St Julian, patron saint of the town of St Julian's, outside Valletta in Malta Photograph: Darrin Zammit Lupi/Reuters

Students of Howard University march from campus to the Lincoln Memorial to participate in the Realise the Dream Rally for the 50th anniversary of the March on Washington Photograph: James Lawler Duggan/Reuters

A woman watches a video of Martin Luther King Jr's 'I Have a Dream Speech' projected on to the side of Fort Independence in Boston, Massachusetts Photograph: Brian Snyder/Reuters

Amhed al-Mekhlafi, 30, a former army soldier, dives into a pool during the men's 50m freestyle final at the Capital Sana'a Swimming Championship in Sana'a, Yemen. Mekhlafi lost a leg in 2005 during a battle against Shia rebels in north-western Yemen Photograph: Khaled Abdullah/Reuters

An aerial view of the Burning Man 2013 arts and music festival in the Black Rock Desert in Nevada Photograph: Jim Urquhart/Reuters

Stunning photos of gorillas, dugongs and mushrooms were among the 43,000 entries from 96 countries to the 2013 wildlife photographer of the year competition. The Natural History Museum in London will announce the overall winners in October.
This image is in the running for the Gerald Durrell award for endangered species: Diana Rebman, US: ‘What made all the physical effort worth it was to see the mother with her two babies.’ This is only the fifth set of mountain gorilla twins ever to be reported in Rwanda’s Volcanoes national park.
To see the rest of the shortlist click here Photograph: Diana Rebman/2013 WPY

Colombia's dancers, Juan David Bedoya Marin and Karla Rotavinsky Cadavid, compete at the Tango World Championship in Buenos Aires, Argentina Photograph: Daniel Garcia/AFP/Getty Images

Palestinian children sit on a donkey in a poverty-stricken district of the town of Khan Younis in the southern Gaza Strip where they live with their families in tents Photograph: Mahmud Hams/AFP/Getty Images

A man uses a bucket of water against a wildfire in Santiago de Besteiros, near Tondela, north Portugal Photograph: Francisco Seco/AP

Palestinians carry the body of Jihad Aslan during his funeral at Qalandiya refugee camp near the West Bank city of Ramallah Photograph: Darren Whiteside/Reuters

Pope Francis photobombs a selfie in Saint Peter's Basilica at the Vatican Photograph: Osservatore Romano/Reuters

Spanish bullfighters wait to do the paseillo, or ritual entrance into the arena before a bullfight, in Toro, Spain Photograph: Daniel Ochoa de Olza/AP

In Sao Paulo members of an anarchist Black Bloc group staged a peaceful walk, blocking roads and shouting slogans, in training for their next big rally scheduled for Brazil's upcoming Independence Day celebrations Photograph: Nacho Doce/Reuters

Palestinian children play on the beach near the Shati refugee camp in Gaza City Photograph: Mohammed Abed/AFP/Getty Images

A young couple kiss as they stand in a shaft of intense sunlight reflected from the glass windows of the new 'Walkie Talkie' tower in central London Photograph: Leon Neal/AFP/Getty Images