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)

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)

This is the amazing moment a heroic hippo saved a gnu from certain death. After being bitten by a crocodile, the large antelope is seen being dragged slowly under the water. But in a miraculous turn of events, a nearby hippo is seen making its way across the water to help the animal in its hour of need. Photo: One of the biggest hippos protects the gnu as it makes its way back to the shoreline, guarding it from any further attacks. (Photo by Vadim Onishchenko/Caters News)

A model wears a creation for Vivienne Westwood's Spring-Summer 2016 ready-to-wear fashion collection, presented during the Paris Fashion Week in Paris, Saturday October 3, 2015. (Photo by Francois Mori/AP Photo)

Belarusian people take part in the Ivan Kupala festival near the town of Rakov, west of Minsk June 27, 2015. The ancient tradition, originating from pagan times, is usually marked with grand overnight festivities. On Kupala night, people sing and dance around campfires, believing it will purge them of their sins and make them healthier. (Photo by Vasily Fedosenko/Reuters)

In this Friday, November 30, 2018 handout photo released by Raindrop Media, Bollywood actress Priyanka Chopra and Nick Jonas celebrate during a mehendi ceremony, a day before their wedding, at Umaid Bhawan in Jodhpur, India. (Photo by Raindrop Media via AP Photo)

A dancer performs during the Gymnastics Rio Gala on Day 12 of the 2016 Rio Olympic Games on August 17, 2016 in Rio de Janeiro, Brazil. (Photo by Clive Brunskill/Getty Images)

People dressed in national clothes sing songs during the regional harvest festival in the town of Dyatlovo, Belarus, November 13, 2015. (Photo by Vasily Fedosenko/Reuters)