People in Mexico wave at U.S. Border Patrol agents on horseback patrolling the U.S.-Mexico border fence near San Diego, California, U.S., November 10, 2016. (Photo by Mike Blake/Reuters)

A worker stack bricks on his head at a brick factory in Lalitpur January 12, 2015. (Photo by Navesh Chitrakar/Reuters)

The Wuppertal Suspension Railways is one a kind elevated railway located in Wuppertak, Germany. It is the oldest elevated railway in the world, though it doesn’t look like it. It is kept in great condition by the government and provides for a great attraction for the tourists. It provides a great overview, as it runs above a number of city streets and a small river. Moreover, since it is powered by electricity, it proves an ecologically clean method of travel for the residents of the city.

“Kilauea Rules”. The most extreme place we put ours kayakers to paddle till now. Photo location: Big Island, Hawaii. (Photo and caption by Alexandre Socci/National Geographic Photo Contest)

The moon illuminates the snow-covered Concordia, the confluence of the Baltoro and Godwin-Austen glaciers, near the world's second highest mountain the K2 (8,000 meters) in the Karakoram mountain range in Pakistan September 6, 2014. While other parts of Pakistan and northern India were flooded, Concordia in the Karakoram mountain range was covered with a seasonally unusual amount of snow. Geographically, Pakistan is a climbers paradise. It rivals Nepal for the number of peaks over 7,000 meters and is home to the world's second tallest mountain, K2, as well as four of the world's 14 summits higher than 8,000 meters. (Photo by Wolfgang Rattay/Reuters)

“DC3 Wreck”. A capture of a US military DC3 plane wreck at the southern black beach in Iceland. Photo location: Iceland. (Photo and caption by Naian Feng/National Geographic Photo Contest)

A giant sinkhole in Guatemala City, on May 31, 2010. More than 94,000 were evacuated as the storm buried homes under mud, swept away a highway bridge near Guatemala City and opened up several sinkholes in the capital. (Photo by Casa Presidencial/Reuters via The Atlantic)