24 hours in pictures

Sacramento, US: Keith Day, who recently became homeless, warms himself next to a campfire at a homeless tent city, which is seeing an increase in population as the economic situation worsens Photograph: Justin Sullivan/Getty Images

Nueva Concepcion, El Salvador: A police special force officer guards an alleged gang member Photograph: Rodrigo Abd/AP

Cape Canaveral, USA: The space shuttle Discovery is illuminated by lights on the launch pad as it is prepared for launch Photograph: Joe Raedle/Getty Images

Xining, China: A Tibetan pilgrim carries his child inside his robe as he prays in a temple in Kumbun monastery Photograph: David Gray/Reuters

Jaisalmer, India: Men smear coloured powder on each other's faces during celebrations for Holi, the Hindu festival of colour Photograph: Gemunu Amarasinghe/AP

Hollywood, USA: Gulls perch on a wall in California Photograph: Mario Anzuoni/Reuters

Nairobi, Kenya: A University of Nairobi student throws stones at police during a protest against the killing of a fellow student allegedly by police Photograph: Tony Karumba/AFP/Getty Images

Bogotá, Colombia: A student gets up close and personal with a Xenesthis immanis tarantula during an exhibition at a school Photograph: William Fernando Martinez/AP

Dharamsala, India: A Tibetan Buddhist Monk in exile makes his way through the Dalai Lama temple during a ceremony to mark 50 years in exile Photograph: Daniel Berehulak/Getty Images

Ashland, USA: Prairie grass is covered with ice in eastern Nebraska Photograph: Nati Harnik/AP

Rawalpindi, Pakistan: Worshippers take part in Eid Milad-un-Nabi celebrations, marking the anniversary of the birth of Islam's Prophet Muhammad Photograph: Emilio Morenatti/AP

Jerusalem, Israel: Youths smoke cigarettes during celebrations for the Jewish holiday of Purim Photograph: Gil Cohen Magen/Reuters

Beit Lahiya, Gaza: A couple celebrate their wedding Photograph: Tara Todras-Whitehll/AP

Tokyo, Japan: A teacher robot is demonstrated by a Tokyo University of Science professor. First developed as a receptionist robot in 2004, it was tested in a real Tokyo classroom earlier this year, although it still cannot do much more than call the register and shout orders like "Be quiet" Photograph: Itsuo Inouye/AP