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 view of the construction site of the Chateau de Guedelon near Treigny in the Burgundy region of France, September 13, 2016. Blacksmiths, stonemasons and quarry men are hard at work in a Burgundy forest building a 13th-century-style castle using the most basic tools and materials, replicating the methods used hundreds of years ago to better understand them. (Photo by Jacky Naegelen/Reuters)

Fossilized whale bones are on display outside the Wati El Hitan Fossils and Climate Change Museum, a UNESCO natural World Heritage site, on the opening day, in the Fayoum oasis, Egypt, Thursday, January 14, 2016. Egypt has cut the ribbon on the Middle East's first fossil museum housing the world's largest intact skeleton of a "walking whale" in an attempt to attract much-needed tourists driven off by recent militant attacks. The construction of the much-hyped Fossils and Climate Change Museum was covered a 2 billion euros (2. 17 billion dollars) grant from Italy, according to Italian Ambassador Maurizio Massari. Its centerpiece is an intact, 37-million-year-old and 20-meter-long skeleton of a legged form of whale that testifies to how modern-day whales evolved from land mammals. The sand-colored, dome-shaped museum is barely discernible in the breathtaking desert landscape that stretches all around. (Photo by Thomas Hartwell/AP Photo)

All throughout history of mankind people were fascinated by time, its flow, and how to measure it. Thus, the science of horology can into being, as people invented more and more sophisticated ways of measuring the passage of time. Truly, it’s one of the most profound characteristics of being a human, to feel and to ponder the meaning of time, its properties, and will we ever be able to move through it, not with it. Now, however, horology is mainly referred to the art of mechanical watchmaking. (Photo by MB&F)

Northeastern girls getting commando training at the Delhi Police Training Centre, Jharoda Kalan on September 4, 2017 in New Delhi, India. For the first time ever, Delhi Police are providing commando training to 40 young women from the Northeast. Once the commando training is over, these girls will be a part of the «Parakram Vans», an initiative taken by Delhi Police against terrorism. (Photo by Manoj Verma/Hindustan Times via Getty Images)

A cat yawns at Nekorobi cat cafe on January 20, 2009 in Tokyo, Japan. Cat cafes, where people can spend time with their favorite cat for about 10 US dollars an hour, are now getting more popular with people living in urban areas. The regular customers are mainly in their 20's to 30's and seaking healing by cats, or people who cannot afford to have pets full time. Some visiters come to the cat cafe three times a week. (Photo by Junko Kimura/Getty Images)

There are many types of collections. Some are formed by purposefully collecting certain objects, such as stamps or coins. However, some collections are only a byproduct of an obsession, a quirk of mind. For example, Paul Brockmann got into the habit of buying his girlfriend and later his wife a dress every time they went ballroom dancing. It might seem excessive to some, but it was his way of showing his affection. Overtime, this collection grew to be enormous, counting 55,000 dresses in total. Basic math tells us that either they went ballroom dancing three times per day for every day of their lives, or he bought them in huge bundles every time.