“Himalayan Dog”. This dog just appeared out of nowhere and followed us for an entire week during our trekking trip in the Himalayan outback. He always used to sleep in front of our tent and guarded us in the nights. When I decided to get up at 4 a.m. to climb the next 5000 m peak for sunrise he accompanied me as well. On the top he was sitting for the entire 30 minutes on this place looking straight into the countryside. Photo location: Ladakh, India. (Photo and caption by Sebastian Wahlhuetter/National Geographic Photo Contest)

Planes land in fog at Heathrow Airport, west London, as heavy fog covers a many parts of the south east, on April 1, 2014. (Photo by Steve Parsons/PA Wire)

People take a photograph at the Kremlin, against the backdrop of the Volga river, in the town of Nizhny Novgorod, Russia, July 10, 2015. Russia will host the 2018 FIFA World Cup soccer tournament. (Photo by Maxim Shemetov/Reuters)

Milena Pino, 15, puts on makeup prior to taking part in a speed competition with horses at the International Livestock Fair Show in Havana March 21, 2015. (Photo by Alexandre Meneghini/Reuters)

Revellers take part in an annual block party known as “Cordao de Prata Preta”, one of the many carnival parties to take place in the neighbourhoods of Rio de Janeiro, February 6, 2016. (Photo by Pilar Olivares/Reuters)

A man with blood on his shirt is evacuated from Brussels Airport in Zaventem, Belgium, on Tuesday, March 22, 2016. (Photo by Dirk Waem/Belga/Zuma Press/TNS)

A boy and a woman run across a railway track as a train approaches in Chengdu, Sichuan province, China, October 8, 2015. Many residents disregard sign prohibiting this kind of illegal crossing and choose to do so to save time, local media reported. (Photo by Hao Fei/Reuters/Western China Metropolis Daily)

Angele Blank, right, and Virginia Promeyrat wait for the start of the Greenwich Village Halloween Parade, Saturday October 31, 2015, in New York. (Photo by Tina Fineberg/AP Photo)