24 hours in pictures

Sao Paulo, Brazil: A dancer performs during the carnival parade of Camisa Verde e Branco samba school Photograph: Andre Penner/AP

Prague, Czech Republic: Vincek, a six-day-old Rothschild giraffe, is presented to the media at Prague zoo Photograph: Petr David Josek/AP

Kastoria, Greece: The town's frozen lake. More than 650 people have died so far in Europe's coldest winter in decades Photograph: Giorgos Nissiotis/AP

Cairo, Egypt: A protester takes cover from the rain during a demonstration organised to call for the expulsion of the Syrian ambassador outside the embassy Photograph: Marco Longari/AFP/Getty Images

Washington, US: President Barack Obama steps out of a Boeing 787 after touring the airplane at the Boeing Company's assembly facility in Everett Photograph: Ted S. Warren/AP

Dakar, Senegal: An anti-government protester holds a Muslim prayer bracelet during a demo against incumbent President Abdoulaye Wade's bid to seek a third term Photograph: Reuters

Sochi, Russia: Maria Hoefl-Riesch of Germany in action during the women's downhill race at the Alpine Skiing World Cup in Krasnaya Polyana Photograph: Roland Schlager/EPA

Comayagua, Honduras: Relatives prepare graves for their family members who died in a prison fire. Angry relatives gathered at the morgue and said the official explanation of a crazed inmate who set fire to his bedding was absurd Photograph: Estbean Felix/AP

Irrawaddy, Delta, Burma: Supporters of Myanmar democracy leader Aung San Suu Kyi wait for her arrival in Pyar Pon Photograph: Soe Than Win/AFP/Getty Images

London, England: A model prepares backstage prior to the Fyodor Golan show during London Fashion Week Autumn/Winter 2012 at Somerset House Photograph: Ian Gavan/Getty Images

Caracas, Venezuela: Musicians of 'El sistema' Simon Bolivar Youth Symphonic Orchestra at Teresa Carreno theatre. Gustavo Dudamel is directing a series of concerts to celebrate the 37th anniversary of the National System of Children and Youth Orchestras of Venezuela Photograph: Leo Ramirez/AFP/Getty Images

London, England: Vladimir Tuychiev of Uzbekistan races during the Men's omnium flying lap at the UCI World Cup track cycling, an official test event for the London 2012 Olympic Games, at the Velodrome in the Olympic Park Photograph: Adrian Dennis/AFP/Getty Images

Tripoli, Libya: Celebrations marking one year since the start of the uprising against the former regime at Martyrs' Square. Crowds across Libya rejoiced at being free of Muammar Gaddafi Photograph: Anis Mili/Reuters

Venice, Italy: A couple in traditional costume at the annual Venice carnival. The city's streets are filled with revellers wearing costumes and masks, during the event that lasts nearly three weeks Photograph: Marco Secchi/Getty Images