Merit Prize Winner: “A Well Earned Rest in the Sahara”. This photo of Moussa Macher, our Tuareg guide, was taken at the summit of Tin-Merzouga, the largest dune (or erg) in the Tadrat region of the Sahara desert in southern Algeria. Moussa rested while waiting for us to finish our 45-minute struggle to the top. It only took ten minutes of rolling, running, and jumping to get back down. The Tadrat is part of the Tassili N'Ajjer National Park World Heritage area, famous for its red sand and engravings and rock paintings of cattle, elephants, giraffes, and rhinos that lived there when the climate was milder. Photo location: Summit of Tin-Merzouga, Tadrat, Tassili N'Ajjer National Park, Algeria. (Photo and caption by Evan Cole/National Geographic Photo Contest)

A man walks beside a “Wrinkles Of The City” creation near the Berlin cathedral in Berlin April 19, 2013. (Photo by Fabrizio Bensch/Reuters)

A wax figure depicting Jennifer Lopez by wax museum Madame Tussauds dressed in a new set of clothes attracts the attention of pedestrians during a press event at a beach bar in Berlin,†Germany, August 21, 2015. (Photo by Jens Kalaene/EPA)

In this January 3, 2018 photo several female Gelada baboons, also known as bleeding-heart baboons, cuddle with their youngs in order to keep warm at the Wilhelma zoo in Stuttgart, Germany. (Photo by Sebastian Gollnow/DPA via AP Photo)

Arlo Dela Cruz and Maica Nicerio-Dela Cruz on their wedding day with the Mayon volcano erupting in the background, in Daraga, Albay, Philippines on January 25, 2018. They were married earlier in the afternoon at Our Lady of the Gate Parish. After their wedding they walked out to Red Labuyo restaurant and the volcano started its eruption. The Mayon volcano continued to erupt Thursday. The airport in Legazpi is closed until at least 31 January 2018. (Photo by ZUMA Press/Alamy Stock Photo)

Festival goers kiss in the “Silent Disco” at the “Music in the Park” stage during the 50th Montreux Jazz Festival, in Montreux, Switzerland, July 9, 2016. (Photo by Anthony Anex/EPA)

A hippopotamus is sprayed with water on a hot summer day at Anna National Zoological Park in Chennai, India on April 26, 2017. (Photo by Arun Sankar/AFP Photo)

Visitors take photos of a child dressed in a traditional costume before a folk performance in Panyu, Guangdong province, China on April 20, 2018. (Photo by Reuters/China Daily)