Cosplayers dressed as She- Ra and Emma Frost pose for a photograph at the MCM Comic Con at ExCeL exhibition centre in London on October 28, 2017. (Photo by Tolga Akmen/AFP Photo)

A man sits waiting for a train on the London Underground in 1890, when the platform floors were still made from wooden floorboards. (Photo by Hi-Story/Alamy Stock Photo)

A man arranges a display of cacti during preparations for the RHS Chelsea Flower Show in London, Britain May 21, 2016. (Photo by Neil Hall/Reuters)

People hold out money as butchers sell their remaining produce of the year at discounted prices during the traditional Christmas Eve auction at Smithfield's market in London December 24, 2015. (Photo by Neil Hall/Reuters)

Revellers watch as police officers dance in the street at the Notting Hill Carnival in west London, August 30, 2015. (Photo by Toby Melville/Reuters)

Tattoo enthusiast Lauren Brock poses to display her body art work during the International London Tattoo Convention in east London, Britain September 26, 2015. (Photo by Neil Hall/Reuters)

Tattoo artists and body art fans from across the globe have descended on London for one of the biggest and most prestigious tattoo conventions. “This is like the Premier League of tattoo artists from all over the world who come here to show their work”, organiser Marcus Beriman said. Photo: Bugz Bonniie displays some of her tattoos. (Photo by Oli Scarff)

A “jungle nymph” is measured during the annual weight-in ZSL London Zoo on August 21, 2014 in London, England. The height and mass of every animal in the zoo, of which there are over 16,000, is recorded and submitted to the Zoological Information Management System. This is combined with animal measurement data collected from over 800 zoos and aquariums in almost 80 countries, from which zoologists can compare information on thousands of endangered species. (Photo by Oli Scarff/Getty Images)