Catherine, Duchess of Cambridge smiles as she is saluted to during the Irish Guards Medal Parade at the Victoria Barracks on June 25, 2011 in Windsor, England. The Duchess of Cambridge and Duke of Cambridge are at the barracks to present service medals to members of the Irish Guards. (Photo by Chris Jackson/Getty Images)

Decorative model Elephants stand in Trafalgar Square on May 4, 2010 in London, England. 260 of the decorative life size baby Elephants have been designed by established and emerging artists including Paul Smith, Marc Quinn and Julien Macdonald and have been placed across the capital in prominent places such as Buckingham Palace, Parliament Square and Trafalgar Square. (Photo by Dan Kitwood/Getty Images)

Men hang at the back of a truck loaded with farm produce along a road in Ikeja district in the commercial capital Lagos, Nigeria December 19, 2016. (Photo by Akintunde Akinleye/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)

The Aurora Borealis (Northern Lights) lights up the sky near the village of Pallas (Muonio region) of Lapland, Finland September 8, 2017. (Photo by Alexander Kuznetsov/Reuters/All About Lapland)

Ariel Winter attends the 4th Annual Just Jared Summer Bash on August 13, 2016 in Los Angeles, California. (Photo by JB Lacroix/Getty Images)

French President Emmanuel Macron performs at the Shrine Africa in Lagos on July 3, 2018. French President Emmanuel Macron has arrived in Abuja for a meeting with his Nigerian counterpart Muhammadu Buhari, in his latest attempt to forge closer ties with English- speaking Africa. (Photo by Ludovic Marin/AFP Photo)

In this Friday, December 4, 2018 photo, a half sunken cruise ship lays on its side, in the Gulf of Elefsina, west of Athens. Dozens of abandoned cargo and passenger ships lie semi-submerged or completely sunken around the Gulf of Elefsina, near Greece’s major port of Piraeus. Now authorities are beginning to remove the dilapidated ships. Some of them have been there for decades, leaking hazards like oil into the environment and creating a danger to modern shipping. One expert calls the abandoned ships “an environmental bomb”. (Photo by Thanassis Stavrakis/AP Photo)