The holder of half a dozen world records will walk across the Grand Canyon on a steel cable with nothing but the Little Colorado River 1,500 feet below on June 23. With no tethers or safety nets, the walk will be the highest tightrope attempt ever for the 34-year-old, at a height taller than the Empire State Building. Last year, Wallenda, a seventh-generation member of the “Flying Wallendas” family of acrobats, became the only person to walk a wire over the brink of Niagara Falls. Photo: Nik Wallenda walks across a tightrope 200 feet above U.S. 41 on January 29, 2013 in Sarasota, Florida. (Photo by Tim Boyles)

In this photo taken on March 16, 2019, 13-year-old Reymark Cavesirano collects left over herring onboard a fishing boat anchored at the mouth of Manila Bay off Navotas City in suburban Manila. Cavesirano, a grade five student, paddles to the anchored fishing boats and helps crew clean their nets, and in exchange collects leftover herring still tangled in the nets. Across the Philippines, there are 5 million child labourers, aged between five and 17, many of them working in dangerous conditions. About 22 million people – a fifth of the population – live below the national poverty line. (Photo by Ted Aljibe/AFP Photo)

Despite the high winds and fright temperatures, about 1/2 dozen brave members of the Coney Island Polar Bear Club took a dip in the Atlantic Ocean at March 14, 2017, just of Stillwell avenue in Coney Island beach in Brooklyn NYC. (Photo by Paul Martinka)

In this photo taken on Monday, October 27, 2014, a cactus stands at a broken window in a damaged house after shelling not far from Donetsk airport in the town of Donetsk, eastern Ukraine. Donetsk, which has lost about 400,000 of its 1 million pre-war population, is bracing to a winter ahead. In a climate like eastern Ukraine's, where temperatures typically stay below zero all winter, the damage to the critical infrastructure and lack of effort to provide adequate shelter to people whose homes were destroyed could literally mean a death from the cold. (Photo by Dmitry Lovetsky/AP Photo)

Discovered in 1952 by French bio-speleologist Henri Coiffait, the waterfall and accompanying sinkhole were fully mapped in the 1980s by the Spéléo club du Liban. The cave is also known as the "Cave of the Three Bridges." Traveling from Laklouk to Tannourine one passes the village of Balaa, and the "Three Bridges Chasm" (in French "Gouffre des Trois Ponts") is a five-minute journey into the valley below where one sees three natural bridges, rising one above the other and overhanging a chasm descending into Mount Lebanon. During the spring melt, a 90–100-metre (300–330 ft) cascade falls behind the three bridges and then down into the 250-metre (820 ft) chasm. A 1988 fluorescent dye test demonstrated that the water emerged at the spring of Dalleh in Mgharet al-Ghaouaghir.

“Tardigrades (commonly known as waterbears or moss piglets) are small, water-dwelling, segmented animals with eight legs. Tardigrades were first discovered in 1773 by Johann August Ephraim Goeze, who called them kleiner Wasserbär, meaning “little water bear” in German. The name Tardigrada means “slow walker” and was given by Lazzaro Spallanzani in 1777. The name water bear comes from the way they walk, reminiscent of a bear's gait. The biggest adults may reach a body length of 1.5 millimetres (0.059 in), the smallest below 0.1 mm. Freshly hatched tardigrades may be smaller than 0.05 mm”. – Wikipedia. Photo: Tardigrades. (Photo by SPL/East News)

“Dover Castle is a medieval castle in the town of the same name in the English county of Kent. It was founded in the 12th century and has been described as the “Key to England” due to its defensive significance throughout history. It is the largest castle in England.

The outbreak of the Second World War in 1939 saw the tunnels converted first into an air-raid shelter and then later into a military command centre and underground hospital. In May 1940, Admiral Sir Bertram Ramsey directed the evacuation of French and British soldiers from Dunkirk, code-named Operation Dynamo, from his headquarters in the cliff tunnels”. – Wikipedia

Photo: The Repeater Station in the subterranean tunnels underneath Dover Castle, which has been restored by English Heritage for a public exhibition on June 3, 2011 in Dover, England. The evacuation of allied soldiers from Dunkirk was masterminded and co-ordinated from the secret command and control centre in the tunnels deep below the castle. (Photo by Matthew Lloyd/Getty Images)