A child dressed as a cat takes part in the Children's Halloween day parade at Washington Square Park in the Manhattan borough of New York October 31, 2015. (Photo by Carlo Allegri/Reuters)

A dog dressed in a costume takes part in the Pet's Halloween Day parade at El Olivar Park in San Isidro, Lima, October 31, 2015. (Photo by Mariana Bazo/Reuters)

Two novice Buddhist monks walk alongside a basket seller to collect alms following a clerics rule of no footwear nor use of umbrellas in Mandalay, Myanmar, Friday, October 9, 2015. (Photo by Hkun Lat/AP Photo)

A general view shows smoke and volcanic ashes billowing from volcano Cotopaxi in Pedregal, Ecuador, late 07 October 2015. (Photo by Jose Jacome/EPA)

Labourers load a three-wheeled vehicle onto the back of a van at the Mercato market in Addis Ababa October 9, 2015. Addis Ababa's “Mercato” – Italian for “market” – is reputedly the biggest open-air market in Africa, lying in the west of the capital. (Photo by Tiksa Negeri/Reuters)

A climber walks on the ridge beneath the eastern peak of the Gamsberg (2385 meters above sea level) near Grabs, Switzerland, Friday, October 3, 2014. (Photo by Gian Ehrenzeller/AP Photo/Keystone)

A racegoer flashes her undies in front of the racing crowd during Caulfield Cup Day at Caulfield Racecourse on October 21, 2017 in Melbourne, Australia. (Photo by Splash News and Pictures)

Students from St Andrews University indulge in a tradition of covering themselves with foam to honour the “academic family” on the lower college lawn on October 23, 2017, in St Andrews, Scotland. (Photo by Jeff J. Mitchell/Getty Images)