Participants of the the goth festival “Wave Gothic Festival” walk in fancy costumes along the festival area in Leipzig, central Germany, Saturday, May 23, 2015. About 20,000 members of the scene are expected to attend one of the world's largest gothic and “dark” culture festivals until May 25, 2015. (Photo by Jens Meyer/AP Photo)

A demonstrator is detained during May Day rallies in Santiago May 1, 2013. (Photo by Ivan Alvarado/Reuters)

Ukrainians pour water on each other on a street in Lviv, Ukraine, 02 May 2016. The tradition of pouring water was an ancient spring ritual of cleansing on first Monday after Orthodox Easter. (Photo by Mykola Tys/EPA)

Kerry Katona carries Peter McDonagh's flag before he faces Peter Krame during their Super welterweight bout at the Bolton Whites Hotel, Bolton, United Kingdom on May 12, 2018. (Photo by Lee Smith/Action Images via Reuters)

Jolon Clinton, 15, (L), and her sister, Halcy, 17, take photos of a fissure near their home on the outskirts of Pahoa during ongoing eruptions of the Kilauea Volcano in Hawaii, U.S., May 14, 2018. (Photo by Terray Sylvester/Reuters)

Pinky Ghelani and Suzzy Wokabi watch a TV broadcast of Britain's Prince Harry and Meghan Markle's royal wedding at the Windsor golf and country club in Nairobi, Kenya May 19, 2018. (Photo by Thomas Mukoya/Reuters)

A boy looks at a six-metre tall luminescent puppet, operated by ten performers, during a preview of Vivid Sydney, promoted as the world's largest festival of light, music and ideas, in Sydney, Australia on May 23, 2018. “Vivid” is a major outdoor cultural event featuring light installations and projections with the annual event this year running from May 25 to June 16, 2018. (Photo by David Gray/Reuters)

Participants perform a dragon dance as they march during a lantern parade marking the start of a month- long “Lotus Lantern Festival” to celebrate the upcoming Buddha' s birthday, in Seoul on April 29, 2017 Buddha' s birthday falls on May 3. (Photo by Ed Jones/AFP Photo)