Guests have breakfast as another guest climbs to gather at the Skylodge Adventure Suites in the Sacred Valley in Cuzco, Peru, August 14, 2015. Tourists taking on an arduous climb up the steep cliff face of Peru's Sacred Valley are being rewarded for their efforts by being able to spend the night in transparent mountaintop sleeping pods at the “Skylodge Adventure Suites”. To reach the pods, visitors need to climb 400 metres of via ferrata (a steel cable and rungs) up the valley side or hike an intrepid trail through zip lines. (Photo by Pilar Olivares/Reuters)

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.

In this Monday, April 27, 2015 photo, a Nepalese man walks over fallen rocks and past a crushed car on the way to Dhunche, Nepal, a village in Langtang National Park, two days after a 7.8-magnatude earthquake hit the region. The photographer, Joe Sieder, said the man was part of a group of Nepalese workers and trekkers who left Syabrubesi earlier that day and hiked about 30 km (19 miles) for 13 hours, mostly over boulder-strewn roads with some small landslides along the way to make their way to a passable road. (Photo by Joe Sieder via AP Photo)

The moon illuminates the snow-covered Concordia, the confluence of the Baltoro and Godwin-Austen glaciers, near the world's second highest mountain the K2 (8,000 meters) in the Karakoram mountain range in Pakistan September 6, 2014. While other parts of Pakistan and northern India were flooded, Concordia in the Karakoram mountain range was covered with a seasonally unusual amount of snow. Geographically, Pakistan is a climbers paradise. It rivals Nepal for the number of peaks over 7,000 meters and is home to the world's second tallest mountain, K2, as well as four of the world's 14 summits higher than 8,000 meters. (Photo by Wolfgang Rattay/Reuters)

A protester carries a piece of wood simulating a weapon during a protest demanding the resignation of Prime Minister Ariel Henry, in the Petion-Ville area of Port-au-Prince, Haiti, Monday, October 3, 2022. (Photo by Joseph Odelyn/AP Photo)

In this Friday, August. 17, 2018, photo, a North Korean waitress prepares to serve dinner to Chinese tourists at the Pegaebong hotel in Samjiyong in North Korea. Chinese businesspeople and tourists are once again flowing over the borders – several large tourist groups were in Samjiyon last week – and South Korean officials are seriously considering ways to help the North improve its roads and railways. (Photo by Ng Han Guan/AP Photo)

A hooded protester throws a petrol bomb to riot policemen during clashes, following a rally marking the 43rd anniversary of a 1973 student uprising against the military dictatorship that was ruling Greece, in Athens, Greece, November 17, 2016. (Photo by Yannis Behrakis/Reuters)

Hawa Omar, 23, a Sudanese woman who fled the conflict in Sudan's Darfur region, is pictured at her temporary shelter in Adre, Chad on July 19, 2023. (Photo by Zohra Bensemra/Reuters)