The competition, which is run by the Royal Observatory Greenwich in association with BBC Sky at Night Magazine, is now in its sixth year and has received over 2,500 entries. Photo: Centre of the Heart Nebula by Ivan Eder (Hungary). Situated 7500 light years away in the “W”-shaped constellation of Cassiopeia, the Heart Nebula is a vast region of glowing gas, energized by a cluster of young stars at its centre. The image depicts the central region, where dust clouds are being eroded and moulded into rugged shapes by the searing cosmic radiation. (Photo by Ivan Eder)

A adorable bear cub cant get enough of playing buckaroo – as it hangs onto its mum splashing about in a river. His mum was attempting to catch a fish supper for the pair as the plucky cub continued to jump on her back. And as she was concentrating on her meal the young bear became a distraction. So she sprung into life with him on her back before he was tossed into the water much to his delight. (Photo by Lisa Sidorsky/Caters News)

A young man weaves palm fronds into the shape of a cross before the start of a Mass to observe Palm Sunday, at the Metropolitan Cathedral, in Managua, Nicaragua, Sunday, March 29, 2015. For Christians, Palm Sunday marks the start of Holy Week ahead of Easter, commemorating Jesus Christ's entrance into Jerusalem, when his followers laid palm branches in his path. (Photo by Esteban Felix/AP Photo)

Children carrying guns and flags or wearing Soviet-style uniforms have become a common sight at Victory Day parades and other events in Russian-controlled Crimea. Russian and Ukrainian human rights activists have warned that such displays point to a growing trend of promoting Russian patriotism among kids on the Crimean peninsula, annexed from Ukraine in 2014. Here: A young Crimean girl wears military-type clothes during a Victory Day celebration in Sevastopol on May 9, 2018. (Photo by Oleksandra Surgan/Radio Free Europe/Radio Liberty)

Two young dancers take pictures while waiting for the start of the Koenji Awa-Odori dance festival, in the Koenji neighborhood of Tokyo. Saturday, August 24, 2019, Started in the 1950s, the Koenji Awa-Odori has grown to be one of Tokyo's largest and most popular summer festivals an estimated 10,000 dancers participating in the dance festival. Hundreds of thousands of spectators gather in the neighborhood to watch the two-day summer spectacle. The event is held on the last weekend of August each year. (Photo by Jae C. Hong/AP Photo)

A young female demonstrator is arrested by police during clashes in the Causeway Bay area of Hong Kong, China on October 6, 2019. Hundreds of thousands of protesters marched through the city's streets in defiance of the new “no-mask” law, which was introduced two days ago as demonstrations roll into a 14th week. (Photo by Rick Findler/EPA/EFE/Rex Features/Shutterstock)

Migrants try to board a truck at Ouistreham ferry port in the hope of reaching the UK on September 12, 2018 in Ouistreham, France. After the clamp down at Calais many young migrants are seeking out new routes to the United Kingdom as stowaways on vehicles making the channel crossing by ferry from French ports. The migrants, of mostly African origin, camp out on the roadside and woodland areas as the authorities prevent the setting up of any camps. (Photo by Christopher Furlong/Getty Images)

As the world marks the International Day of the Girl Child, women's rights activists point to progress on a wide array of issues but say more needs to be done to protect girls from child marriage, sexual assault and other forms of exploitation. Here is a selection of pictures showing the daily lives of girls across the globe, all taken by female Associated Press photojournalists. Here: In this December 14, 2015, file photo, a young clown rides in the back of a car following a procession to the Basilica of Our Lady of Guadalupe in Mexico City. Hundreds belonging to various clown associations made their annual pilgrimage to the Basilica to pay their respects to the Virgin of Guadalupe, Mexico's patron saint. (Photo by Rebecca Blackwell/AP Photo)