Lindsay Heimbach goes airborne while sledding down a hill on Mt. Lemmon December 27, 2008. (Photo by James Gregg/Arizona Daily Star)

Measuring just five feet at its widest point, the ultra-thin home was unveiled in the Polish capital of Warsaw on Sunday, October 21, 2012. Photo: The Keret House is squeezed into the space between two apartment buildings in Warsaw. There's a four-inch gap between the apartment buildings to either side. A perforated steel facade was used to allow in more light. (Photo by Andrea Meichsner/The New York Times)

Every year, in the Rostov region of Russia, a group of 40 young and not so young rural workers compete in the Bison Track Show, or more affectionately known as: Russian Flying Tractor Racing. In front of crowds numbering up to 30,000 people, a series of smoke spilling, monstrous farming machines tear round an 8km mud track, plowing through lakes and dirt mounds, their turbos screaming and tyres scrabbling to find grip.

A plane carrying a wing walker crashed at an air show and exploded into flames Saturday, killing the pilot and stunt walker, authorities said. The crash of the 450 HP Stearman happened at around 12:45 p.m. at the Vectren Air Show near Dayton in front of thousands of horrified spectators. No one else was hurt.

Photo: A wing walker performs at the Vectren Air Show just before crashing, Saturday, June 22, 2013, in Dayton, Ohio. The crash killed the pilot and the stunt walker instantly, authorities said. (Photo by Thanh V. Tran/AP Photo)

Michiko Ohashi (C), wearing a costume decorated with snacks, performs with other members of pop group Pottya at a fan meeting celebrating her birthday in Tokyo, Japan, October 16, 2016. Competition is cutthroat among Japan's thousands of pop idol wannabes, but a unique concept is winning fame for a band of “chubby” girls deploying their cheeky cuteness to combat prejudices against obesity. (Photo by Kim Kyung-Hoon/Reuters)

“This grey adult male seal enjoys a good grin while lying on the beach”. (Photo by Michael Hutch/SplashdownDirect via Rex USA)

Mark Wagner, the collage artist, challenges viewers to examine their relationship with money and the capitalist society in which we live. Photo: “Way of the Dinosaur”, cut one-dollar bills. (Photo by Mark Wagner)

Technicians check a CRH high-speed train at Shanghai Hongqiao High-speed train base on December 28, 2011 in Shanghai, China. China's railway stations have started today to sell tickets for the 2012 Spring Festival travel season scheduled to run between January 8th and February 16th, centred around the Chinese New Year which this year falls on January 23rd. (Photo by ChinaFotoPress/Getty Images)