Revellers celebrate "Ash Monday" by participating in a colourful "flour war", a traditional festivity marking the end of the carnival season and the start of the 40-day Lent period until the Orthodox Easter,in the port town of Galaxidi, some 215 km (134 miles) north west of Athens, March 18, 2013. The revellers "fight" by throwing coloured flour, charcoal dust and powder painting until they essentially run out of supplies. (Photo by Yannis Behrakis/Reuters)

A fireball erupts from a 16-inch gun on the battleship USS Wisconsin during a live fire exercise in the Persian Gulf, October 13, 1990. The ship is in the Gulf as part of Operation Desert Shield. (Photo by John Gaps III/AP Photo)

Singer Halsey arrives to the 2018 amfAR Gala New York at Cipriani Wall Street on February 7, 2018 in New York City, USA. (Photo by Splash News and Pictures)

In this Tuesday, September 12, 2017 photo, Amornrat Simapsaisan, a local shop manager, watches before she ate watermelon salad with bamboo worms, at Inspects in the Backyard restaurant, Bangkok, Thailand. Tucking into insects is nothing new in Thailand, where street vendors pushing carts of fried crickets and buttery silkworms have long fed locals and adventurous tourists alike. But bugs are now fine-dining at the Bangkok bistro aiming to revolutionize views of nature’s least-loved creatures and what you can do with them. She tucked in quite happily to her watermelon and cricket salad on a recent evening. “It’s tasty. It’s munchy”, she said. (Photo by Sakchai Lalit/AP Photo)

“Photo mechanic” and photographer Ionut Caras creates surreal concepts by combining the everyday with the unthinkable. His use of light and tone takes the viewer into a bizarre and beautiful world only seen in storybooks and our dreams. Photo: “The observer”. (Photo by Ionut Caras)

“Early morning in Mandawa, rural Rajasthan: it was the morning of Diwali and the streets were swept by smiling women in brightly coloured sarees as I took an early morning cup of chai. Celebrations started later, when darkness fell”. (Photo by Hamish Scott-Brown/Guardian Witness)

Respect, Kronotsky nature reserve, Russia. The photographer’s cat, Ryska – her name means little lynx in Russian – stands outside their cabin and with aggressive posturing warns off a fox. In winter, foxes would regularly visit the cabin searching for food. If one peered in at the window, possible when the snow was deep, Ryska would sit on the other side, fur raised, and growl. When outside, she would hold her ground. The foxes were not always frightened and so encounters could be a sort of dance. (Photo by Igor Shpilenok/Unforgettable Behaviour/NHM)

Though schools around the globe have different start dates, calendars and traditions, the first day of a new term is an exciting time filled with the prospects of gaining more knowledge, making new friends and building community. Here: Schoolchildren attend their first lesson on Knowledge Day in the town of Turov, Zhytkavichy District, Gomel Region, Belarus on September 1, 2017. Knowledge Day marks the beginning of a new school year in Belarus and is celebrated on September 1. (Photo by Viktor Drachev/TASS via Getty Images)