Floating on clear deep water and reflections near the cave entrance. Visitors can either bring their own kayaks or rent boats from the local community to paddle deep inside the cave and marvel at its wonders on March 2015 at Tham Khoun Ex, Laos. Tham Khoun Xe, commonly known as the Xe Bang Fai River Cave, in Laos, has over 15km of passages filled with awe-inspiring views and wide expanses of water. Photographer, John Spies, 59, captured scenes from the entrances of the huge underground river passages, intricate cave formations and views from a passage high above the water. The cave is formed by the Xe Bang Fai river, a major tributary of the Mekong and in the dry season can be traversed using inflatable kayaks. (Photo by John Spies/Barcroft Media/ABACAPress)

A jogger runs on the bank of Donaukanal channel in central Vienna, Austria, September 5, 2016. (Photo by Heinz-Peter Bader/Reuters)

A reef shell lies on a beach as the sun sets on Lady Elliot Island located north-east of the town of Bundaberg in Queensland, Australia, June 10, 2015. UNESCO World Heritage delegates recently snorkelled on Australia’s Great Barrier Reef, thousands of coral reefs, which stretch over 2,000 km off the northeast coast. Surrounded by manta rays, dolphins and reef sharks, their mission was to check the health of the world's largest living ecosystem, which brings in billions of dollars a year in tourism. Some coral has been badly damaged and animal species, including dugong and large green turtles, are threatened. UNESCO will say on Wednesday whether it will place the reef on a list of endangered World Heritage sites, a move the Australian government wants to avoid at all costs, having lobbied hard overseas. Earlier this year, UNESCO said the reef's outlook was “poor”. (Photo by David Gray/Reuters)

Policemen guard Poland's Supreme Court as a protester lies on the pavement in Warsaw, Poland, on Thursday, April 22, 2021. A disputed disciplinary body within Poland's Supreme Court is examining a motion that could result in the arrest of a judge who has become a symbol of the fight for an independent judiciary. (Photo by Czarek Sokolowski/AP Photo)

Addis Ababa police officers take part in a parade to display their new uniforms, and their readiness for the upcoming Ethiopian parliamentary and regional elections, in Addis Ababa, Ethiopia, June 19, 2021. (Photo by Baz Ratner/Reuters)

Members of the Chinese military orchestra march past a screen showing the Chinese Communist flag on Tiananmen Square before a celebration marking the 100th founding anniversary of the Chinese Communist Party, in Beijing, China, 01 July 2021. China celebrates on 01 July the 100th anniversary of the founding of the ruling Chinese Communist Party. (Photo by Roman Pilipey/EPA/EFE)

Swan Uppers try to capture a swan and it's Cygnets on the River Thames near Windsor, England, during Swan Upping, with Windsor Castle in background, Tuesday July 20, 2021. The ancient tradition of Swan Upping is the annual census to gauge the numbers and health of the swan population on the River Thames. (Photo by Steve Parsons/PA Wire via AP Photo)

People wade through a road flooded by heavy rain in Kurume, Fukuoka prefecture, western Japan, Saturday, August 14, 2021. Torrential rain pounding southwestern Japan triggered a mudslide early Friday that swallowed some people and was threatening to cause flooding and more landslides in the region. (Photo by Kyodo News via AP Photo)