People wearing costumes walk during Halloween in Sierra Madre, California, U.S., October 31, 2017. (Photo by Mario Anzuoni/Reuters)

Armed women attend a rally to show support to the Houthi movement in Sanaa, Yemen January 13, 2018. (Photo by Khaled Abdullah/Reuters)

A masked reveller hangs from an inflatable balloon during the first day of the carnival in Venice, Italy, January 23, 2016. (Photo by Manuel Silvestri/Reuters)

A worker works at a plant of Hyundai Motor in Asan, South Korea, January 27, 2016. (Photo by Kim Hong-Ji/Reuters)

Men pull as a boy stands on a soap cutter in a soap factory in Idlib province, Syria January 30, 2016. (Photo by Ammar Abdullah/Reuters)

Revellers parade for Gavioes da Fiel samba school during carnival in Sao Paulo, Brazil, February 6, 2016. (Photo by Paulo Whitaker/Reuters)

Revellers take a break during the Carnival 2016 parade in Port-au-Prince, Haiti, February 8, 2016. (Photo by Andres Martinez Casares/Reuters)

A worker collects rubber sap at a farm in Songon village, north of Abidjan, February 3, 2016. (Photo by Luc Gnago/Reuters)