Gizzard, a chihuahua is held by his owner at the 31st Annual Tompkins Square Halloween Dog Parade in New York, U.S., October 23, 2021. Last year the parade was cancelled due to the coronavirus pandemic. (Photo by Caitlin Ochs/Reuters)

A jogger is seen running at Hampstead Heath with London in the background on June 1, 2021. Britain sees temperatures increasing for the second day in a row after the mercury hit 25C (77 Fahrenheit) for the warmest day of the year so far on Bank Holiday Monday. (Photo by Joshua Bratt/London News Pictures)

People feed the birds in Battery Park in the Manhattan borough of New York, December 18, 2014. Hart has been feeding the birds three times a week for the last three years. (Photo by Carlo Allegri/Reuters)

Urban photographer Roman Robroek spent five years scouring the continent for the grandest examples of forgotten architectural beauty. Here: Watch your step on this Polish spiral staircase. (Photo by Roman Robroek/South West News Service)

Members of the Pussyfooters dance at the Krewe of Cleopatra Mardi Gras parade in New Orleans, Friday, February 2, 2018. Mardi Gras season is kicking into high gear with a slew of major parades throughout New Orleans. Although Carnival season officially began Jan. 6, the festivities really kick into high gear the two weekends ahead of Fat Tuesday. This year Fat Tuesday is Feb. 13. (Photo by Gerald Herbert/AP Photo)

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)

An Indian white tiger cools off in a pond in its enclosure at Chhat Bir Zoo on the outskirts of Chandigarh on May 22, 2016. Temperatures have soared to a scorching 51 degrees Celsius in one Indian city, meteorologists said, with the ferocious heat setting a new national record. Northern Phalodi wilted as the mercury reached a new high on May 20, equivalent to 123.8 Fahrenheit, beating a 60-year-old record. (Photo by Shammi Mehra/AFP Photo)

Coloured X-ray of a barn owl. A physicist has used X-ray to create an extraordinary collection of artwork. Arie van't Riets pictures reveal birds, fish, monkeys and flowers in an incredible new light. The 66-year-old, from Bathmen in the Netherlands, began X-raying flowers as a means to teach radiographers and physicians how the machine worked. But after adding a bit of colour to the pictures, the retired medical physicist realised the potential for an exciting new collection of art. (Photo by Arie van't Riet/Barcroft Media)