A figure of a skeleton is seen painted in a hallway of the house built underground by Manuel Barrantes in San Isidro de Perez Zeledon, Costa Rica, March 14, 2016. Barrantes started digging through red soil and volcanic rock on his farm 12 years ago to build his subterranean house, between 15 and 63 feet (4.57 and 19.2m) underground. The dwelling, which Barrantes says provides a peaceful and comfortable home for him and his family away from noise pollution and the effects of climate change, now covers about 2,000 square feet (185.8 square metres). (Photo by Juan Carlos Ulate/Reuters)

Soldiers stand in front of a floral decoration during celebrations to commemorate the 70th anniversary of the establishment of the Vietnam People's Army at the National Convention Center in Hanoi December 20, 2014. The Vietnam People's Army was founded on December 22, 1944 and led by General Vo Nguyen Giap in Cao Bang province, initially with only 34 members. (Photo by Reuters/Kham)

A supporter welcomes US army convoy as it enters Czech Republic in Harrachov, Sunday, March 29, 2015. The “Dragoon Ride” convoy started last week from Estonia and passed through Latvia, Lithuania and Poland before entering the Czech Republic on a return journey to a German base. (Photo by Petr David Josek/AP Photo)

Horse Racing – Crabbie's Grand National Festival – Aintree Racecourse April 10, 2015: Racegoers react during the 17.15 Weatherbys Wealth Management Champion Standard Open National Hunt Flat Race. (Photo by Andrew Boyers/Reuters)

A farmer is seen hanging from a tree during a rally organized by Aam Aadmi (Common Man) Party (AAP) in New Delhi April 22, 2015. The farmer hanged himself from a tree during a political rally in New Delhi on Wednesday, in what appeared to be a desperate protest against the hardship felt by many people scratching a living in rural India. Four people climbed the tree to try to save the man after he was seen hanging. (Photo by Adnan Abidi/Reuters)

A woman watches the rain from inside a stranded vehicle on a flooded street in Mianyang, Sichuan, China on July 11, 2018. (Photo by China News Service via Reuters)

Tourists from the Middle East take pictures at Vrelo Bosne nature park in Ilidza near Sarajevo, Bosnia and Herzegovina, August 19, 2016. They discovered mountainous Bosnia, where half the population is Muslim, after the Arab Spring which destabilized many traditional holiday destinations such as Libya, Tunisia and Egypt. (Photo by Dado Ruvic/Reuters)

Aviator Frantisek Hadrava moves Vampira, an ultralight plane based on the U.S.-design of light planes called Mini-Max, out of a garage in the village of Zdikov, Czech Republic, August 23, 2016. Frantisek thought driving to work for 14 minutes was too much, so he built an plane to cut the commute by half. (Photo by David W. Cerny/Reuters)