The British Ecological Society has announced the winners of its annual photography competition, Capturing Ecology. Taken by international ecologists and students, the winning images will be exhibited at the society’s joint annual meeting in Ghent in December. Here: Overall runner-up; Toucan, Mark Tatchell. (Photo by Mark Tatchell/British Ecological Society)

First graders of a cadet's lyceum attend a ceremony to mark the start of the new school year in Kiev, Ukraine, September 1, 2015. September 1 marks the start of a new academic year for students in Ukraine.(Photo by Valentyn Ogirenko/Reuters)

1: Dubai's Burj Khalifa is the tallest building in the world, but perhaps not for long. Saudi Arabia has announced plans to build a 1 kilometer (3,280 foot) tower into the sky, to be named the Jeddah Tower, scheduled for completion in 2020. The Burj Khallifa currently stands at 2,716 ft. (Photo by Matthias Seifert/Reuters)

A Cambodian villager rides a buffalo during the Pchum Ben festival, the festival of death, at Vihear Suor village in Kandal province on October 1, 2016. Thousands of Cambodians descended on the small village northeast of the capital on October 1 to cheer on the annual water buffalo race that marks the end of the 15-day festival for the dead. (Photo by Chor Sokunthea/AFP Photo)

A view of the Sheikh Zayed highway in Dubai and some high rise buildings, November 8, 2007. (Photo by Steve Crisp/Reuters)

An installation with a copy of a tank is seen at a villager's house in the village of Vits, Belarus November 8, 2016. (Photo by Vasily Fedosenko/Reuters)

A vendor drinks water as she waits for customers at a roadside flower market in Ahmedabad, India, February 8, 2017. (Photo by Amit Dave/Reuters)

People look at a Christmas tree decorated with colourful lights at a residential compound in Beijing on December 8, 2017. (Photo by Nicolas Asfouri/AFP Photo)