24 hours in pictures

Tacoma, US: Police officers kneel in front of the caskets of police officers Ronald Owens, Tina Griswold, Greg Richards and Mark Renninger during a public memorial service Photograph: Stephen Brashear/guardian.co.uk

Baghdad, Iraq: A victim's hand in the rubble at the scene of a bomb blast near the Finance Ministry Photograph: Ahmad Al-Rubaye/guardian.co.uk

London, UK: Gordon Brown and Alistair Darling arrive for a cabinet meeting at 10 Downing Street ahead of the pre-budget report Photograph: Anthony Devlin/guardian.co.uk

Rome, Italy: Activists from the environmental group Legambiente wear masks of world leaders as they hold a "Stop global warming" protest in Piazza del Popolo Photograph: Andreas Solaro/guardian.co.uk

Edmonton, US: Steam rises from nearby oil refineries Photograph: Andy Clark/guardian.co.uk

Henan province, China: Tourists look through windows at the famous Shaolin Temple Photograph: Peter Parks/guardian.co.uk

Linfen, China: Smog down a main street of in one of the cities with the worst air pollution in the world Photograph: Peter Parks/guardian.co.uk

Hefei, China: A child next to piles of cabbages at a market Photograph: Jianan Yu/guardian.co.uk

Gelsenkirchen, Germany: A polar bear underwater at the zoo Photograph: Martin Meissner/guardian.co.uk

Cairo, Egypt: Workers walk down one of the under construction tunnels of Line 3 of the Cairo Metro Photograph: Mike Nelson/guardian.co.uk

Lima, Peru: Members of the Special Forces during a parade for the Independence Anniversary Photograph: Paolo Aguilar/guardian.co.uk

Kabul, Afghanistan: A woman passes by slips hanging in front of a shop Photograph: Alexandre Meneghini/guardian.co.uk

Rome, Italy: Pope Benedict XVI waves from his popemobile after the traditional prayer to celebrate the Immaculate Conception Photograph: Pier Paolo Cito/guardian.co.uk

Cotoca, Bolivia: Two monkeys perform during Virgin Day celebrations Photograph: Jorge Saenz/guardian.co.uk

Jakarta, Indonesia: A gardener trims a potted plant Photograph: Romeo Gacad/guardian.co.uk

Washington, US: White Mountain Apache dancers from the Fort Apache Reservation in Arizona during the 2009 US Captiol Christmas tree lighting ceremony Photograph: Chip Somodevilla/guardian.co.uk