Ricardo Azevedo rides his Honda NX 200 motorbike, which he converted to be powered by water, in Salto, northwest of Sao Paulo, Brazil, August 6, 2015. The Sao Paulo civil servant built the motorbike, which can cover up to 500 kilometres (311 miles) fuelled by just one litre of water. Dubbed “Moto Power H2O” the bike is powered by the process of electrolysis, which breaks the water molecule down into its constituent elements. (Photo by Nacho Doce/Reuters)

Women in costumes walk as they participate in Halloween celebrations in the downtown of Seoul, South Korea, October 31, 2015. (Photo by Kim Hong-Ji/Reuters)

The Photographers 2015 runs from 25 November to 23 December at Osborne Samuel and Beetles+Huxley, London. Here: Untitled, 1950, by Bert Hardy. (Photo by Bert Hardy/Beetles+Huxley & Osborne Samuel)

Karima Adebibe, the newly crowned face of Lara Croft, poses, with a Burmese python on the eve of the release of the record breaking new video game “Lara Croft Tomb Raider; Legend” at The Barbican on April 6, 2006 in London, England. (Photo by Gareth Cattermole/Getty Images)

A period of relative stability has put the Iranian capital No1 on the list of world cities that have achieved biggest improvements in liveability over the past five years, as calculated by the Economist Intelligence Unit. The “most improved” top 10 contains some unexpected names. So, eg, the fourth place: Abidjan, Ivory Coast. Latest ranking: 128; Ranking five years ago: 131; Five-year index movement: 3.8%. Here: A supporter of Ivory Coast president Alassane Ouattara campaigns in a market in the city’s Koumassi quarter. (Photo by Sia Kambou/AFP Photo)

A tourist stands on the shore of a private beach in Naama Bay, Sharm el-Sheikh, south Sinai, Egypt, Sunday, November 8, 2015. Britain's foreign secretary says airport security in many cities will need to be overhauled if it is confirmed the Russian plane crash in the Sinai was caused by a bomb planted by the Islamic State group or someone inspired by the militants. (Photo by Vinciane Jacquet/AP Photo)

Over the years a large population of grey herons have made an unlikely home in urban Amsterdam. Julie Hrudova documents how the birds integrate into city life. Here: Hundreds of herons come to the city during winter to find food and shelter. (Photo by by Julie Hrudova/The Guardian)

“Beryl Cook, (10 September 1926 – 28 May 2008) was an English artist best known for her original and instantly recognisable paintings of people enjoying themselves in pubs,girls shopping or out on a hen night. Drag shows or a family picnicing by the seaside or abroad – tangoing in Buenos Aires or gambling in Las Vegas. She had no formal training and did not take up painting until middle age”. – Wikipedia. Photo: “Ladies Night”, 1991. Artwork by Beryl Cook.