Farmer Zhang Xianping rides his pig "Big Precious" during an interview with the media, in Zhangjiakou, Hebei province, China, November 2, 2015. Zhang, a pig breeder, instead of killing it, decided to keep the two-year-old "Big Precious" as pet when its weight reached 600 kg, according to local media. (Photo by Reuters/China Daily)

Romanian military doctors and medical students sit on a bus behind steamy windows before the National Day parade in Bucharest, Romania, Thursday, December 1, 2016. Military planes and helicopters flew over the Romanian capital Thursday as thousands turned out to celebrate the national day, marking the date when the country reunified with Transylvania in 1918. (Photo by Vadim Ghirda/AP Photo)

Flying pigeons pass over Nepalese street vendors near the earthquake damaged UNESCO World Heritage Site, Durbar Square in Kathmandu on May 20, 2015. Nearly 8,500 people have now been confirmed dead in the disaster, which destroyed more than half a million homes and left huge numbers of people without shelter with just weeks to go until the monsoon rains. (Photo by Ishara S. Kodikara/AFP Photo)

Soldiers from 12 Mechanized Brigade perform a simulated casualty evacuation at the Ministry of Defence training area at Copehill Down on Salisbury Plain on March 9, 2012 in Wiltshire, England. The Defence Secretary Philip Hammond visited the military facility to meet soldiers from the Brigade who are shortly to deploy to Afghanistan for Operation Herrick 16, and troops from the 3rd Battalion, the Yorkshire regiment which lost five of the six men who died this week in the deadliest single attack in Afghanistan since 2001. (Photo by Matt Cardy/Getty Images)

Komodo Judo by Andrey Gudkov. Finalist, Amphibians & Reptiles. Two large male Komodo dragons hissing angrily at each other in Indonesia’s Komodo national park. Komodo dragons can grow up to 8ft. (Photo by Andrey Gudkov/Wildlife Photographer of the Year 2015)

Bonbibi, Treehouse Point, Fall City, WA. The Bonbibi is balanced on two steel yokes. The yokes spread out the load and allow for tree growth and movement in the wind. A small deck hangs from the beams below and uses the treehouse itself to shelter guests. (Photo by Pete Nelson)

City buildings stand beyond the giant excavated hole left by the Mir mine, a former open pit diamond mine, in Mirny, Russia, on Tuesday, November 12, 2013. OAO Alrosa, the world's largest diamond producer, raised about $1.3 billion in an oversubscribed share sale from investors including Oppenheimer Funds Inc. and Lazard Ltd.'s asset-management unit, First Deputy Prime Minister Igor Shuvalov said. (Photo by Andrey Rudakov/Bloomberg)

This picture was taken in the 1890's and shows a group of loggers hauling a heavy load. It is hard to even picture how they got the logs stacked that high. It is also hard to imagine how they keep it from tipping over.