A picture of Moon Ji-sung, a high school student who died in the Sewol ferry disaster, hangs in her room in Ansan April 7, 2015. Her dream was to be a flight attendant. Nearly a year after the Sewol ferry sank on April 16, 2014, with the death of 250 students, some families keep their children’s bedrooms intact to remember and honour their loved ones. More than 300 people, most of them students and teachers from Danwon High School, are dead, or missing and presumed dead, after the Sewol ferry sank on a routine trip from the port of Incheon, near Seoul, to the holiday island of Jeju. (Photo by Kim Hong-Ji/Reuters)

High-wire artist Kane Petersen successfully walks a tightrope 300 metres above the ground at Eureka Skydeck on September 16, 2015 in Melbourne, Australia. The walk was the highest tightrope walk ever attempted in the Southern Hemisphere. The stunt is to mark the arrival of the film “The Walk” to Australian cinemas in October. The stunt saw Kane mimic the film's French high-wire artist Philippe Petit, who successfully walked between the twin towers of the World Trade Center in 1974. (Photo by Scott Barbour/Getty Images)

The Haʻikū Stairs, also known as the Stairway to Heaven or Haʻikū Ladder, is a steep hiking trail on the island of Oʻahu. The trail began as a wooden ladder spiked to the cliff on the south side of the Haʻikū Valley. It was installed in 1942 to enable antenna cables to be strung from one side of the cliffs above Haʻikū Valley to the other. A building to provide a continuous communication link between Wahiawā and Haʻikū Valley Naval Radio Station was constructed at the peak of Puʻukeahiakahoe, elevation about 2,800 feet (850 m). The antennae transmitted very low frequency radio signals from a 200,000-watt Alexanderson alternator in the center of Haʻikū valley. The signals could reach US Navy submarines as far away as Tokyo Bay while the submarines were submerged.

Large waves break at Burleigh Heads on the Gold Coast,, Queensland, Australia, 05 June 2016. Recent wild weather unleashed heavy rainfalls, powerful winds and abnormally high tides in Southeast Queensland and northern New South Wales. (Photo by Dan Peled/EPA)

Visitors hold ice blocks to cool themselves in hot weather at a water park on June 23, 2016 in Chongqing, China. Citizens and visitors escaped high temperature at a water park in Yangren Jie (also known as Foreigner Street), Nan'an District of south China's Chongqing. (Photo by VCG/VCG via Getty Images)

Smoke billows from a high-rise apartment building in west London Wednesday, June 14, 2017. A massive fire raced through the building early Wednesday, emergency officials said. (Photo by Rick Findler/PA Wire via AP Photo)

Base jumpers leap from the 300-metre high skydeck of Malaysia's landmark Kuala Lumpur Tower against the backdrop of the city's skyline in Kuala Lumpur on September 30, 2018 during the annual International KL Tower Base-Jump event. (Photo by Manan Vatsyayana/AFP Photo)

Winner. “I took this vertical image in the Quarry Bay district of Hong Kong during the dusk ‘blue hour’, when there was a perfect balance between the ambient light in the sky and the artificial lights of the high-rise residential buildings”. (Photo by Jatinder Heer/The Guardian)