In this photo taken Friday, September 4, 2015, tourists Sarah and John Scott from Worcester, England, take a step back as a male silverback mountain gorilla from the family of mountain gorillas named Amahoro, which means “peace” in the Rwandan language, unexpectedly steps out from the bush to cross their path in the dense forest on the slopes of Mount Bisoke volcano in Volcanoes National Park, northern Rwanda. Deep in Rwanda's steep-sloped forest, increasing numbers of tourists are heading to see the mountain gorillas, a subspecies whose total population is an estimated 900 and who also live in neighboring Uganda and Congo, fueling an industry seen as key to the welfare of the critically endangered species as well as Rwanda's economy. (Photo by Ben Curtis/AP Photo)

A visitor takes in a view of the downtown district from Twin Peaks on Friday, January 9, 2015, in San Francisco. (Photo by Marcio Jose Sanchez/AP Photo)

The six-months-old female koala cub holds on to the back of zoo keeper Lena at the zoo in Duisburg, Germany, 23 October 2015. The yet unnamed baby weighs 580 grams. (Photo by Roland Weihrauch/EPA)

People watch as workers inflate a near-10 metre high giant spider by Singaporean artist Jackson Tan in Singapore's Marina Bay financial district on February 6, 2017. The spider is one of several inflatable creatures that will form the Art-Zoo, a section created by Singaporean artist Jackson Tan for the iLight Marina Bay annual light-art festival in the city-state. (Photo by Roslan Rahman/AFP Photo)

In this timed-exposure night photo taken early on February 12, 2017, Mount Sinabung volcano spews reddish smoke and ash, as seen from the Karo district in North Sumatra province. Activity levels have increased in the past week, with Sinabung shooting hot ash clouds into the sky dozens of times, according to the local volcano monitoring agency. (Photo by AFP Photo/Stringer)

Hindu women apply “sindhur”, or vermillion powder, on the face of a woman after worshipping the idol of the Hindu goddess Durga on the last day of the Durga Puja festival in Chandigarh, India October 11, 2016. (Photo by Ajay Verma/Reuters)

The Big Island's Mauna Loa Volcano erupts on November 28, 2022 on the Island of Hawaii. For the first time in almost 40 years, the biggest active volcano in the world erupted prompting an emergency response on the Big Island. (Photo by Andrew Richard Hara/Getty Images)

People dance to celebrate Midsummer Eve during sunset at the Amager Strandpark in Copenhagen, Denmark, June 23, 2021. (Photo by Hannah McKay/Reuters)